1. a The University of Michigan, School of Public Health, Industrial Hygiene Program, Ann Arbor, MI 48109-2029
2. b Abbott Laboratories, Corporate Industrial Hygiene Laboratory, Dept. 038A, 1401 Sheridan, North Chicago, IL 60064
3. c Abbott Laboratories, Pharmaceutical Products Division, D-405, Abbott Park, IL 60064
4. d University of California, Center for Occupational and Environmental Health, School of Public Health, Berkeley, CA 94720