912
Ben Greenfield, Beyond Training: Mastering Endurance, Health, and Life (Las Vegas: Victory Belt Publishing, 2014), 231.
913
«Sleep to Be an All-Star: Winners Sleep, Losers Weep,» Speed Endurance, November 2013, .
914
Ibid.
915
Ruan, «Awesome Federer Interview,» The Ultimate Tennis Blog, January 15, 2010, .
916
Thomas Burrows, «Roger Federer's Formula for Final? Renting TWO Houses to Avoid Being Disturbed by His Young Family,» Daily Mail, July 11, 2015, .
917
Alec Fenn, «How Gareth Bale and Real Madrid Sleep Their Way to the Top,» BBC Sport, April 21, 2015, .
918
Jack Crone, «Manchester City Players Given Wallpaper with Special Sleep-Inducing Patterns in Their Bedrooms at Club's £200m Training Base,» Mail Online, January 3, 2015, .
