• Author: Dijk, D. J. D. G. Beersma S. Daan
• Title: EEG power density during nap sleep: reflection of an hourglass measuring the duration of prior wakefulness
• Year: 1987
• Reference Type: Journal Article
• Journal/Book Title: J. Biol. Rhythms
• Volume: 2
• Issue: 3
• Pages: 207-19
• Date of Publication: Sunday, 20 December 1987