1. Assistant Professor, University of Michigan Medical Center, and Research and Education Associate, U. S. Veterans Administration Hospital, Ann Arbor, Michigan 48105
2. Chairman, Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan 48104
3. Research Technologist, U. S. Veterans Administration Hospital, Ann Arbor, Michigan 48105
4. Resident, Department of Oral Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48104