1. ABC News/Washington Post, 1985. Survey by ABC News/Washington Post, September 19–September 23, 1985. iPOLL Databank, The Roper Center for Public Opinion Research, University of Connecticut. Accessed on July 16, 2007 (http://www.ropercenter.uconn.edu.monstera.cc.columbia.edu:2048/ipoll.html).
2. The mortality of doctors in relation to their smoking habits:A preliminary report;Doll;British Medical Journal,1954
3. Gallup, 1954a. Survey by Gallup Organization, June 12–June 17, 1954. iPOLL Databank, The Roper Center for Public Opinion Research, University of Connecticut. Accessed on July 16, 2007 (http://www.ropercenter.uconn.edu.monstera.cc.columbia.edu:2048/ipoll.html).
4. Gallup, 1954b. Survey by Gallup Organization, January 9–January 14, 1954. iPOLL Databank, The Roper Center for Public Opinion Research, University of Connecticut. Accessed on July 16, 2007 (http://www.ropercenter.uconn.edu.monstera.cc.columbia.edu:2048/ipoll.html).
5. Gallup, 1969. Survey by Gallup Organization, July 24–29, 1969. iPOLL Databank, The Roper Center for Public Opinion Research, University of Connecticut. Accessed on July 16, 2007 (http://www.ropercenter.uconn.edu.monstera.cc.columbia.edu:2048/ipoll.html).