Bourne JE, Sauchelli S, Perry R, Page A, Leary S, England C, Cooper AR. Health benefits of electrically-assisted cycling: a systematic review. Int J Behav Nutr Phy. 2018 Nov 21;15(1):116. doi: 10.1186/s12966-018-0751-8
Willett W, Greenland S, MacMahon B, Trichopoulos D, Rothman KJ, Thomas D. The discipline of epidemiology. Science. 1995 Sep 8;269(5229):1325-6. doi: 10.1126/science.7660105
Rothman KJ. Journal policies on conflict of interest. Science. 1993 Sep 24;261(5129):1661. doi: 10.1126/science.8378766