1. Karmanos Cancer Institute/Family Medicine, Wayne State University, Detroit, Michigan 40202, and Research Center for Group Dynamics, University of Michigan, Ann Arbor, Michigan 48109;
2. Psychology Department, University of Connecticut, Storrs, Connecticut 06269;
3. Department of Sociology, University of Wisconsin, Madison, Wisconsin 53706;
4. University of Arkansas, Fayetteville, Arkansas 72701;