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
Xu J, Evans J, Coon C, Copley-Merriman K, Su Y. Measuring patient-reported outcomes in advanced gastric cancer. Ecancermedicalscience. 2013;7:351. doi: 10.3332/ecancer.2013.351.