1. Cancer facts and figures 1991;American Cancer Society,1991
2. Cancer facts and figures 1991;American Cancer Society,1991
3. Cancer facts and figures 1991;American Cancer Society,1991
4. A Smoking cessation program for the dental office;Christen,1990
5. The health consequences of using smokeless tobacco: a report of the advisory committee to the surgeon general;U.S. Department of Health and Human Services;NIH Publication No. 86-2874,1986