1. United States Public Health Service.The health consequences of smoking. Washington, D.C: United States Department of Health, Education, and Welfare, 1979.
2. Gritz, E. R. Patterns of puffing in cigarette smokers. In N. A. Krasnegor (Ed.),Self-administration of abused substances: Methods for study (NIDA Research Monograph 20). DHEW, ADAMHA, July 1978.