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
Forns J, Vegas O, Julvez J, Garcia-Esteban R, Rivera M, Lertxundi N, Guxens M, Fano E, Ferrer M, Grellier J, Ibarluzea J, Sunyer J. Association between child cortisol levels in saliva and neuropsychological development during the second year of life. Stress Health. 2014 Apr;30(2):142-8. doi: 10.1002/smi.2504