Sources:
http://www.guinnessworldrecords.com/world-records/highest-altitude-(cycling)
http://www.guinnessworldrecords.com/world-records/highest-altitude-bicycle-race
https://healthyliving.azcentral.com/cycle-high-altitude-2495.html
http://www.bikeradar.com/mtb/gear/article/technique-how-to-air-drop-offs-16333/
http://www.guinnessworldrecords.com/world-records/fastest-time-to-cycle-10000-km-
http://www.cyclingweekly.com/fitness/training/13-ways-increase-average-cycling-speed-144937
http://www.guinnessworldrecords.com/world-records/468637-greatest-distance-cycled-in-a-year-umca
https://www.bicycling.com/training/fitness/last-going-long-0
http://www.guinnessworldrecords.com/world-records/102647-greatest-distance-cycled-no-hands
http://www.cyclingweekly.com/news/latest-news/how-to-ride-no-handed-191823
http://www.guinnessworldrecords.com/world-records/longest-distance-cycling-backwards
https://www.cascadehealthandfitness.com/news/2015/05/21/cycling-backwards-improves-performance/
http://www.guinnessworldrecords.com/world-records/farthest-distance-cycling-underwater
http://www.foxnews.com/health/2013/08/29/aqua-cycling-new-underwater-workout.html
http://www.latimes.com/health/la-he-aquacycle-20170902-htmlstory.html
http://www.nytimes.com/2013/06/07/health/aqua-cycling-is-an-underwater-spinning-workout.html
http://www.aquastudiony.com/aquacycling/#
http://www.guinnessworldrecords.com/world-records/432533-longest-spinning-static-cycling-class
http://www.guinnessworldrecords.com/world-records/208937-longest-marathon-static-cycling
https://shop.vescape.com/en/blog/6-how-to-exercise-on-a-stationary-bike