804,731 PRACTICAL Practical concepts for dose selection in chronic toxicology and carcinogenicity : studies in rodents : February 1996 / [ECETOC [European Centre for Ecoto-xicology and Toxicology of Chemicals]. - Brussels : ECETOC, 1996. - [4], 55 s. ; 30 cm (Monograph/ECETOC, ISSN 0773-6347-25 ; nr 25)