Christensen T, Riis AH, Hatch EE, Wise LA, Nielsen MG, Rothman KJ, Toft Sorensen H, Mikkelsen EM. Costs and efficiency of online and offline recruitment methods: a web-based cohort study. J Med Internet Res. 2017 Mar 1;19(3):e58. doi: 10.2196/jmir.6716
Cann CI, Rothman KJ. Epidemiology of laryngeal cancer. In: Fried MP, editors. The larynx. Boston: MA. Little, Brown and Co; 1988.