Health Education Research Advance Access originally published online on May 20, 2004
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Health Education Research, Vol. 19, No. 4, 430-439,
August 2004
© 2004 Oxford University Press
Follow-up study of a school-based scalds prevention programme
1 Department of Psychology, University of Auckland, Private Bag 92019, Auckland, New Zealand
2Correspondence to: N. Harré; E-mail: n.harre{at}auckland.ac.nz
 |
Abstract |
|---|
 Top Abstract IntroductionMethodResultsDiscussionReferences |
|---|
This paper describes the follow-up evaluation of a school-based scalds prevention programme designed to teach children about scalds hazards and encourage safe family practices. It involved two classroom sessions and a homework exercise that targeted five safety practices. The programme was taught to 28 classes in 14 schools in Waitakere City, New Zealand by Public Health Nurses (PHNs). Children (n = 116) aged 10–11 years from three of the schools in ethnically diverse, low/middle-income areas were assessed for their knowledge of scalds hazards 1 year after the programme. They recalled a mean of 7.46 out of 10 hazards, which was almost equivalent to children in an earlier evaluation who recalled 7.62 hazards immediately after the teaching. Altogether, 65–79% of children reported that each of the four safety items provided were at least temporarily used as intended, with 29–55% reporting that they were still in use 1 year later. Interviews with children's parents (n = 18) indicated that the majority of their hot water practices were not optimally safe prior to the programme and that many had adopted the suggested practices. While the PHNs were positive about the programme, they suggested teachers could deliver it as part of the school curriculum.
This paper describes the follow-up evaluation of a school-based scalds prevention programme designed to teach children about scalds hazards and encourage safe family practices. It involved two classroom sessions and a homework exercise that targeted five safety practices. The programme was taught to 28 classes in 14 schools in Waitakere City, New Zealand by Public Health Nurses (PHNs). Children (n = 116) aged 10–11 years from three of the schools in ethnically diverse, low/middle-income areas were assessed for their knowledge of scalds hazards 1 year after the programme. They recalled a mean of 7.46 out of 10 hazards, which was almost equivalent to children in an earlier evaluation who recalled 7.62 hazards immediately after the teaching. Altogether, 65–79% of children reported that each of the four safety items provided were at least temporarily used as intended, with 29–55% reporting that they were still in use 1 year later. Interviews with children's parents (n = 18) indicated that the majority of their hot water practices were not optimally safe prior to the programme and that many had adopted the suggested practices. While the PHNs were positive about the programme, they suggested teachers could deliver it as part of the school curriculum.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
Burns and scalds are a leading cause of injury to children, with those under 5 years especially at risk (Injury Prevention Research Unit, 1997
; Joseph et al., 2002). In New Zealand, thermal injuries are the fourth most common category of unintentional injury resulting in hospitalization for children 0–4 years, ahead of pedestrian and motor vehicle occupant injuries (Injury Prevention Research Unit, 2003). Scalds are more common than other burns, with hot drinks and food, hot tap water (including baths), and jugs and kettles being the main causes (Ytterstad and Sogaard, 1995; Injury Prevention Research Unit, 1997; Corrarino et al., 2001; Joseph et al., 2002). At least 9081 children in New Zealand received medical treatment for burns and scalds injuries in the 2001/02 year, of which 79% were pre-schoolers [based on claims to the national accident insurer (ACC, 2002)]. A total of 4732 children aged 0–14 were hospitalized for these injuries from 1990 to 1999 (Injury Prevention Research Unit, 2001). While ‘passive’ environmental interventions are important in helping reduce these injuries (Ytterstad et al., 1998) it is also important to look at family practices related to scalds (Glik et al., 1993), especially in the kitchen and bathroom, and with regard to hot drinks.
This paper describes the follow-up study of a school-based intervention programme aimed at improving the hot water safety practices of families with children. The intervention was developed in Waitakere City, New Zealand by Safe Waitakere, a Community Injury Prevention Project. A school-based intervention was seen as desirable after difficulties were experienced reaching parents of young children directly (Harré and Polzer-Debruyne, 1998), and a survey of children aged 7–13 years revealed that they were frequently involved in tasks such as preparing hot drinks, running baths for themselves and bathing siblings (Harré et al., 1998).
The programme is based on two classroom lessons and a homework exercise. It is pictorially based to help make it accessible to primary school children and families with English as a second language. The first classroom session involves a discussion in which the children are invited to share their experiences of scalds. A flipchart is then used to illustrate four scald hazards around the home, involving electric jugs, hot drinks, pots on the stove and running a bath. For each of these there is one picture showing unsafe practices and a second showing safe practices (see Table I and Figure 1). After working through the flipchart, homework exercises are given out. The second session takes place approximately 1 week later. Children are asked about their experience with the homework exercise, those that returned them are given a family participation certificate and safety practices are reviewed.
|
|
The homework exercise consists of 6 pages. The first page explains that this is a family exercise, gives statistical information on scalds and a date for returning the exercise to school. Each of the other pages concentrates on one of the hazards, with a picture of the safe practice, and instructions that involve the child and parent identifying whether their household practices are safe and ticking in the appropriate box. If their practice is unsafe, a list of possible changes is provided. If they are not able or prepared to make the changes they are asked to comment.
Several items are included with the exercise—a thermometer to measure hot tap water (the only item that is required to be returned to school), an information sheet on how to lower hot water temperature, a hook for the jug cord, a sticker for the stove showing pots at the back with handles turned in stating ‘Use back elements first, turn pot handles in’, a plastic label that can be hung over the bath tap stating ‘Run cold water first’ and a drink coaster stating ‘Place hot drinks in the middle of the table’ (see Table I).
An evaluation of an earlier version of the programme (that did not include the stove sticker, bath hook or drink coaster) conducted at ethnically diverse schools from low/middle-income areas of Waitakere City showed large increases in children's knowledge of scald hazards and reported changes in home safety (Harré and Coveney, 2000). Return rates of 61–85% were obtained for the homework exercise, and both parents and school staff gave positive feedback. The programme appeared equally effective with all the ethnic groups involved, which was considered especially important as children from lower socioeconomic backgrounds and ethnic minorities may be at greater risk for injury (Grieve and Williams, 1985).
Given the positive results of the initial evaluation, the local Health Funding Authority funded 50 programme kits, that included an A3 flipchart, templates of the homework exercise suitable for photocopying, an instruction booklet, the results of the evaluation and bulk supplies of the items included with the homework exercise. In the trials of the earlier version, a school-based Public Health Nurse (PHN) taught the programme. After consultation between Safe Waitakere and the regional PHNs, it was decided that widespread delivery by PHNs should be piloted and the nurses would aim to deliver the programme to children aged approximately 8–9 years at each of the schools in Waitakere City. A 2-hour training session was held and it was delivered to 28 classes in 14 primary schools in 2001.
The PHN who taught the earlier version of the programme was part of the Safe Waitakere working group that designed it and was highly knowledgeable about injury prevention. The children themselves received pre-testing, potentially alerting them to the importance of the programme, and some of the classroom teaching was observed by a researcher. One aim of the current study was to measure the effectiveness of the programme, when delivered by PHNs after a short training session. A second aim was to see how readily the PHNs incorporated the teaching into their schedule and if they found the programme easy to use. A third aim was to examine the children's knowledge of scalds hazards 1 year after being taught the programme and to compare this with the results from the trials of the earlier version, in which knowledge was measured shortly after the programme. We were also interested in whether the programme had an impact on family practices 1 year later.
|
Method |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
Participants
Of the 14 schools that were taught the programme in 2001, three were chosen for the evaluation, using two criteria. (1) It was important that a relatively large number of children had been taught the programme. (2) We wanted schools from low/middle-income areas, with ethnically diverse students. Using a socioeconomic indicator developed by the Ministry of Education that codes schools from decile 1 (low) to 10 (high) socioeconomic strata, two of the schools selected were rated three, providing 40 and 41 participants, and one was rated six, providing 35 participants (total n = 116). A range of ethnicities were represented at each school with children of European, Pacific, Maori and Asian descent.
All the children were in Year 6 and aged 10–11 years. There were 73 boys and 43 girls. Sixty-six (57%) indicated they had one or more younger siblings. All the children who took part had been taught the programme in 2001 and were present on the day of testing.
A total of 18 parents took part in a telephone interview. All the children eligible for the evaluation from two of the participating schools took home an information sheet asking their parent if they were willing to take part. Twenty parents/caregivers agreed to participate; two were unable to be contacted.
Five of the six PHNs who delivered the programme in 2001 participated in a 10-min telephone interview; one of the nurses was no longer employed in the district.
The safety knowledge of the children 1 year after being taught the programme was compared to the knowledge of the children in the earlier study, who received the programme (intervention group) and who did not receive the programme (control group). The children in the earlier study were tested shortly after the teaching. Participants in the intervention group were from a decile 3 school, and included a Year 2 class (n = 21), a Year 4 class (n = 22) and a Year 6 class (n = 27). The control group was from another decile 3 school, with a Year 2 class (n = 22), a Year 4 class (n = 22) and a Year 6 class (n = 27). In the control group, there were 38 boys and 33 girls; in the intervention school, there were 31 boys and 32 girls. See Harré and Coveney (Harré and Coveney, 2000) for further details.
Procedure
Information sheets were provided for the school principals, teachers and the PHNs, with consent to participate received from all concerned. All children and their parents were provided with an information sheet. Parents were able to withdraw their child if they requested; none did so. Verbal assent was gained from all the children prior to the start of the interview.
Each child was taken out of the classroom and interviewed individually. The children were shown the four pictures from the flipchart illustrating unsafe practices and asked to identify anything that looked unsafe. The pictures contained 10 hazards that were identical to those used in the earlier study (see Table I). The children at two of the three schools were also asked if they could remember the safe temperature for hot water.
The children were then shown each of the items from the homework exercise (the hook, stove sticker, coaster and bath hook) and asked whether they remembered them. For each one they remembered, they were asked if they still had it at home, and its current and past use. The answers were coded into three categories: (1) in current intended activity, (2) temporarily used as intended and (3) never used as intended. If the item was not currently being used as intended, they were further asked what had happened to it. This answer was coded as follows:
- Lost, not sure: responses indicating they were not sure what had happened to it, or it was lost, e.g. ‘we moved house, no longer know where it is [jug hook]’ and ‘don't know what happened to it, it fell off easily [bath label]’.
- Worn out damaged: either the item wore out or became damaged, e.g. ‘it got wet—we threw it out [coaster]’ and ‘it was on the oven, but my little cousin took it off [pot sticker]’.
- Inappropriate use: the item was being put to an inappropriate use in the home, or not being used at all, e.g. ‘use for the radio and sometimes the iron [jug hook]’ and ‘it's stuck in my sticker book [pot sticker]’.
- Seen as not needed: the item was not seen as needed to improve safety, e.g. ‘we have a gas kettle [jug hook]’ and ‘we use our other coasters [coaster]’.
Finally, the children were asked if they remembered whether their hot water temperature had been within the safe range when they measured it. After the interview was completed they were instructed not to discuss it with the other children until all the interviews were finished.
The parents who had agreed to be interviewed were telephoned. They were asked if they remembered each activity from the homework exercise and if the activities had any impact on their family practices. Their responses to the latter question were categorized as to whether they said they were safe at the time of the exercise, were not safe and had made a change or were not safe and had not made a change.
Each PHN was asked questions on the following: the feasibility of including teaching the programme as a regular part of their schedule and any anticipated demands on their time that would be given priority, the effect of the level of commitment of the teaching staff, the effectiveness of the homework exercises, the appropriate age group and how often the programme should be taught, the advantages and disadvantages of PHNs teaching the programme, and any improvements. Their responses were examined for common themes.
|
Results |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
The number of hazards identified by the children in the current study was compared to the number identified in the post-test of the earlier study (Harré and Coveney, 2000
). This enabled a three-way comparison between children who had never received the programme (the control group in the earlier study), children's knowledge immediately after the programme (intervention group in the earlier study) and children's knowledge 1 year after the programme (current study). The mean numbers of hazards identified by children in each of the three schools in the current study, compared with the intervention and control schools in the earlier study, are outlined in Table II.
|
Analysis of variance revealed a significant group effect [F(2, 247) = 230.05, P < 0.05] with post hoc Tukey's tests showing that the present study group and the intervention group in the earlier study did not differ from each other, but both groups identified more hazards than the control group from the earlier study.
A second ANOVA was conducted using the three schools in the current study to see if there were any significant differences in their hazard identification scores. Gender differences were also examined. This revealed that there was no effect for gender, but an effect for school [F(2, 113) = 3.82, P < 0.05] with post hoc Tukey's tests showing that the mean test score of School 2 differed from the mean test score of School 3.
Children in the earlier study, and in two of the schools in the current study, were asked if they knew the safe temperature of hot tap water (i.e. between 50 and 55°C). In the earlier study, 4.2% of the control group and 54% of the intervention group correctly identified the safe temperature. In the current study, 15.8% did so.
Recall of the individual items in the Hot Water Safety kit was high, with 94% of the children remembering the hook for the electric jug cord, 88% the hot drinks coaster, 96% the pot sticker and 91% the label for the bath tap. The children were asked if they had ever used the item as intended (even though it may now be no longer in use). Altogether, 65% reported at least temporarily using the jug hook as intended, 70% the coaster, 71% the stove sticker and 79% the bath label. The extent to which each of these items was reported as still in use, as well as what had happened to items no longer in use, is outlined in Table III. Children were also asked if they recalled measuring their home hot water temperature and 89% did so. Of these, 63% reported it as being in the safe range, 16% in the unsafe range and 22% did not remember.
|
The number of parents/caregivers who reported that each activity in the homework exercise had an impact on their family practices is shown in Table IV. The exercise appears to have had more impact on electric jug use, cooking pot safety and bath safety than on hot drink practices.
|
Five themes were identified from the interviews with PHNs: (1) feasibility of the PHNs delivering the programme, (2) advantages of PHN delivery, (3) disadvantages of PHN delivery, (4) effect of commitment of teaching staff and (5) parental commitment. These issues and some typical responses are outlined in Table V. Overall, the themes suggest that while the PHNs enjoyed delivering the programme, they believe it may be better for it to be taught by classroom teachers.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
The results from this study suggest that the school-based scalds prevention programme may have at least a medium-term impact on children's knowledge of scalds hazards and on family practices. The study also indicated that the programme is effective when taught by public health nurses after a brief training session. This extends the findings of the earlier study which measured only short-term effectiveness when the children were taught by a highly committed public health nurse under closely monitored conditions (Harré and Coveney, 2000
). It is also an advance on evaluations of other school-based burns programmes that have only tested (and shown) short-term knowledge retention (Eckelt et al., 1985; Varas et al., 1988; Grant et al., 1992; Lewis et al., 1994).
One reason for the high level of knowledge shown by the children may be that the programme was intrinsically interesting and provided them with opportunities for autonomy and competence—factors found to enhance motivation and learning (Ryan and Deci, 2000). The children's enthusiasm was reflected in spontaneous comments made to the interviewers. One child reported that after testing the hot water temperature in his own home and finding it within the safe range, he then tested the hot water temperature in his grandmother's home and found it to be too high. He reported that she called in a tradesman who adjusted the cylinder!
It is also notable that the information was presented to the children in multiple forms. In class they are shown pictures as well as discussing safety practices, and at home they are again required to use both visual and verbal channels. Paivio's dual-coding theory states that there are two systems for the representation and processing of information—a verbal system for linguistic information and a non-verbal system for image-based information (Eysenck and Keane, 1998). It is likely that an additive memory effect is obtained when information is coded and stored in both systems (Vasu and Howe, 1989). Children's recall of the safe temperature for hot water was not as good as in the earlier study. This may be because this information was more abstract and not as rich as the information about the scalds hazards, leading to memory loss. Recall may be improved by including a sticker for the hot water cylinder stating the safe temperature among the items given to the children as part of the homework exercise.
Children may also have been constantly reminded about potential hazards and safe practices by the ongoing use of the items received as part of the homework exercise. The percentage of children who reported each item being at least temporarily used as intended was 65–79%, with 29–55% still using each as intended. The variability in current use rates could be partly due to the durability of the individual items. The hook supplied for the electric jug cord was apparently not very strong, with children making comments such as ‘it fell down, the sticky wore out’. The coaster for hot drinks was made of thick paper and therefore vulnerable to moisture damage. In contrast, the items with higher durability, the plastic bath label and the stove sticker (which would have to be actively removed once in place), were more commonly still in use.
Few parents reported having safe practices prior to the programme (less than one-third to half for each potential hazard), but many parents reported improving their practices in response to the homework exercise. For example, only three of the 16 parents who recalled the stove exercise reported safe practices prior to the programme, with 11 reporting safety changes. In the interviews parents made comments such as ‘Yes, I now always put the pots at the back, if I forget my child always reminds me’, ‘Most definitely, made me aware of dangers, now do everyday—the cord has been made safe and the jug is kept well back’ and ‘Yes, I now always run cold water first, didn't think before’. These findings indicate both that the programme targets practices that can be improved in many homes and that families may be willing to make changes.
The programme seemed to encourage a high degree of teacher commitment (as reported by the PHNs), a key factor in the success of school-based health programmes [e.g. (Briggs and Hawkins, 1994)]. The PHN deliverers were also enthusiastic about the programme and saw it as a good opportunity to enhance their relationship with the school. However, they reported that there are many occasions when other duties would need to take priority, such as mass immunizations and individual case referrals. They also found it difficult to follow-up on the homework exercises. An alternative is teachers delivering the programme as part of the health and safety curriculum.
While boys and girls had equivalent knowledge of the scalds hazards, one of the schools, with a low decile (socioeconomic status) rating, showed a significantly different score to the higher socioeconomic status school. We could find no obvious reason for this, with the two lower socioeconomic status schools having similar demographic profiles and with equally positive responses about the programme from the PHNs responsible for each. It is important to note also that even at the school with the lowest mean knowledge score, the children were able to identify many more hazards than at the control school from the earlier study.
There were a number of limitations to the evaluation. First, the hazard identification exercise did not include a pre-test and therefore we do not know what the children's knowledge was prior to the programme. However, the earlier study on children from the same city indicated that most were able to identify very few, if any, hazards prior to the teaching. It seems very unlikely that the children in the current study would have acquired their knowledge of scalds hazards prior to the programme. Not pre-testing these children also meant the programme could be assessed under more natural conditions (i.e. without the additional intervention of a pre-test), which was one of the aims of this study. We cannot, of course, guarantee that the children in this study had the same characteristics as those in the earlier study. They were, on average, slightly older, as the earlier study included children from the junior, middle and senior divisions of the school, and this study was only on senior division children. They were also from a different cohort as they received the programme 2 years later.
A second limitation is that the data on the safety practices and items was collected by self-report. Self-report always includes the possibility that participants may overstate their injury prevention practices (Paulhus and Reid, 1991; Gielen et al., 1995). Actually visiting the homes of families could have verified the presence of the safety items, but information about behavioral practices and the history of the safety items could not be gathered in this way. Home visits would also be difficult to arrange and extremely expensive.
The third limitation of note is that we were able to interview only 18 parents from around 75 eligible families. These parents would almost certainly be more interested in school programmes than the average parent. Therefore, they were probably keener to implement the practices recommended. The PHNs themselves commented that some parents are more committed to homework activities such as those in this programme than others. Offering larger incentives or approaching parents during school events could increase the number of parents willing to participate. While we also gained information on the safety items from the children, who were not a self-selected group, we believe that considerable caution needs to be taken when attempting to generalize the parents' reports to the likely impact of the programme on families as a whole.
The overall evidence from this study suggests that this programme educates children about scalds hazards in the home, and may well lead to improvements in family practices through homework activities and the provision of safety items that serve as ongoing reminders. The practices advocated were simple and convenient, and appeared readily absorbed by children who are eager to learn and in the process of developing habits. Efforts are underway to obtain further sponsorship for region-wide distribution of the programme.
|
Acknowledgments |
|---|
We are very grateful to the Waitakere Public Health Nurses and the schools who took part in the study. The Safe Waitakere working group on injuries to children is also thanked, particularly Margaret Devlin and Toni Dale. The Health Funding Authority provided the funding for the programme.
|
References |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionReferences |
|---|
ACC (2002) ACC Injury Statistics 2002 (1st edn). Section 17: Children's Claims. ACC, Wellington.
Briggs, F. and Hawkins, R.M.F. (1994) Follow-up data on the effectiveness of New Zealand's national school based child protection program. Child Abuse and Neglect, 18, 635–643.[CrossRef][ISI][Medline]
Corrarino, J.E., Walsh, P.J. and Nadel, E. (2001) Does teaching scald burn prevention to families of young children make a difference? A pilot study. Journal of Pediatric Nursing, 16, 256–262.[CrossRef][Medline]
Eckelt, K., Fannon, M., Blades, B. and Munster, A.M. (1985) A successful burn prevention program in elementary schools. Journal of Burn Care and Rehabilitation, 6, 509–511.[Medline]
Eysenck, M.W. and Keane, M.T. (1998) Cognitive Psychology: A Student's Handbook, 3rd edn. Psychology Press, Hove.
Gielen, A.C., Wilson, M.E.H., Faden, R.R., Winsow, L. and Harvilchuck, J.D. (1995) In-home injury prevention practices for infants and toddlers: the role of parental beliefs, barriers and housing quality. Health Education Quarterly, 22, 85–95[ISI][Medline]
Glik, D.C., Greaves, P.E., Kronenfeld, J.J. and Jackson, K.L. (1993) Safety hazards in households with young children. Journal of Pediatric Psychology, 18, 115–131.
Grant, E., Turney, E., Bartlett, M., Winbon, C. and Peterson, H.D. (1992) Evaluation of a burn prevention program in a public school system. Journal of Burn Care and Rehabilitation, 6, 703–707.
Grieve, R. and Williams, A. (1985) Young children's perceptions of danger. British Journal of Developmental Psychology, 3, 385–392.
Harré, N. and Coveney, A. (2000) School-based scalds prevention: reaching children and their families. Health Education Research, 15, 191–202.
Harré, N. and Polzer-Debruyne, A. (1998) A community-based programme for the prevention of burns and scalds to pre-school children. Early Child Development and Care, 142, 9–22.
Harré, N., Field, J. and Polzer-Debruyne, A. (1998) New Zealand children's involvement in home activities that carry a burn or scald risk. Injury Prevention, 4, 266–271.
Injury Prevention Research Unit (1997) Scalds. IPRU Fact Sheet 10. Injury Prevention Research Unit, University of Otago, Dunedin.
Injury Prevention Research Unit (2001) Injury to Children in New Zealand resulting in Death or Hospitalisation. IPRU Fact Sheet 22. Injury Prevention Research Unit, University of Otago, Dunedin.
Injury Prevention Research Unit (2003) Injury Causes by Age. IPRU Fact Sheet 29. Injury Prevention Research Unit, University of Otago, Dunedin.
Joseph, K.E., Adams, C.D., Goldfarb, W. and Slater, H. (2002) Parental correlates of unintentional burn injuries in infancy and early childhood. Burns, 28, 455–463.[CrossRef][ISI][Medline]
Lewis, B., Kaplon, S. and Weinberg, K. (1987) Do children retain what they are taught? Journal of Burn Care and Rehabilitation, 15, 298–302.
Paulhus, D. and Reid, D. (1991) Enhancement and denial in socially desirable responding. Journal of Personality and Social Psychology, 60, 307–317.[CrossRef][ISI]
Ryan, R. and Deci, E. (2000) Self-determination theory and the facilitation of intrinsic motivation, social development and well-being. American Psychologist, 55, 68–78.[CrossRef][Medline]
Varas, R., Carbone, R. and Hammond, J.S. (1988) A one-hour burn prevention program for grade school children: its approach and success. Journal of Burn Care and Rehabilitation, 9, 69–71.[Medline]
Vasu, E.S. and Howe, A.C. (1989) The effect of visual and verbal modes of presentation on children's retention of images and words. Journal of Research in Science Teaching, 26, 401–407.[CrossRef]
Ytterstad, B. and Sogaard, A.J. (1995) The Harstad injury prevention study: prevention of burns in small children by a community-based intervention. Burns, 21, 259–266.[CrossRef][ISI][Medline]
Ytterstad, B., Smith, G.S. and Coggan, C.A. (1998) Harstad injury prevention study: prevention of burns in young children by community based intervention. Injury Prevention, 4, 176–180.
Received on December 28, 2002; accepted on June 26, 2003
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||