Lavie, P (May 1986). "Ultrashort sleep-waking schedule. III. 'Gates' and 'forbidden zones' for sleep". Electroencephalography and Clinical Neurophysiology. 63 (5): 414–25. doi:10.1016/0013-4694(86)90123-9. PMID2420557.
Strogatz, SH; Kronauer, RE; Czeisler, CA (July 1987). "Circadian pacemaker interferes with sleep onset at specific times each day: role in insomnia". The American Journal of Physiology. 253 (1 Pt 2): R172-8. doi:10.1152/ajpregu.1987.253.1.R172. PMID3605382.
Lavie, P (May 1986). "Ultrashort sleep-waking schedule. III. 'Gates' and 'forbidden zones' for sleep". Electroencephalography and Clinical Neurophysiology. 63 (5): 414–25. doi:10.1016/0013-4694(86)90123-9. PMID2420557.
Strogatz, SH; Kronauer, RE; Czeisler, CA (July 1987). "Circadian pacemaker interferes with sleep onset at specific times each day: role in insomnia". The American Journal of Physiology. 253 (1 Pt 2): R172-8. doi:10.1152/ajpregu.1987.253.1.R172. PMID3605382.