Group activity

    • ↑ Zhang ZF, Morgenstern H, Spitz MR, Tashkin DP, Yu GP, Marshall JR, Hsu TC, Schantz SP (December 1999). "Marijuana use and elevated risk of squamous cell carcinoma of the top and neck". ↑ Hashibe M, Straif K, Tashkin DP, Morgenstern H, Greenland S,...