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Northrup DA, Ashley MJ, Ferrence R.Northrup DA, et al.Can J Public Health. 1998 Jul-Aug;89(4):224-8. doi: 10.1007/BF03403921.Can J Public Health. 1998.PMID: 9735512Free PMC article.
Alexander DL, Cohen JE, Ferrence RG, Ashley MJ, Northrup DA, Pollard JS.Alexander DL, et al. Among authors: northrup da.Can J Public Health. 1997 Jul-Aug;88(4):230-1. doi: 10.1007/BF03404787.Can J Public Health. 1997.PMID: 9336090Free PMC article.No abstract available.