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Greenfield RE, Ellwein LB, Cohen SM.Greenfield RE, et al. Among authors: ellwein lb.Carcinogenesis. 1984 Apr;5(4):437-45. doi: 10.1093/carcin/5.4.437.Carcinogenesis. 1984.PMID: 6705147
Cohen SM, Greenfield RE, Ellwein LB.Cohen SM, et al. Among authors: ellwein lb.Environ Health Perspect. 1983 Mar;49:209-15. doi: 10.1289/ehp.8349209.Environ Health Perspect. 1983.PMID: 6832093Free PMC article.