APA

National Cancer Institute (U.S.), . (1972). Less harmful ways of smoking: a workshop of the second world conference on smoking and health held in London, England Sept. 20-24, 1971. [Washington, D.C: .

Chicago

National Cancer Institute (U.S.), . 1972. Less harmful ways of smoking: a workshop of the second world conference on smoking and health held in London, England Sept. 20-24, 1971. [Washington, D.C: .

Harvard

National Cancer Institute (U.S.), . (1972). Less harmful ways of smoking: a workshop of the second world conference on smoking and health held in London, England Sept. 20-24, 1971. [Washington, D.C: .

MLA

National Cancer Institute (U.S.), . Less harmful ways of smoking: a workshop of the second world conference on smoking and health held in London, England Sept. 20-24, 1971. [Washington, D.C: . 1972.