7 November 2014, aeon.co: Broken sleep by Karen EmslieArkiveret 5. september 2015 hos Wayback Machine Citat: "...Then, in the late 19th century, everything changed. The lights got turned on...In Daily Rituals: How Artists Work (2013), Mason Currey describes the routines of famous writers and artists, many of whom are early risers, and several segmented sleepers. Currey found that many hit on the pattern of segmented sleep by accident...""
22 February 2012, bbc.co.uk: The myth of the eight-hour sleep Citat: "..."It's not just the number of references - it is the way they refer to it, as if it was common knowledge," Ekirch says...By the 1920s the idea of a first and second sleep had receded entirely from our social consciousness..."
7 November 2014, aeon.co: Broken sleep by Karen EmslieArkiveret 5. september 2015 hos Wayback Machine Citat: "...Then, in the late 19th century, everything changed. The lights got turned on...In Daily Rituals: How Artists Work (2013), Mason Currey describes the routines of famous writers and artists, many of whom are early risers, and several segmented sleepers. Currey found that many hit on the pattern of segmented sleep by accident...""
