Bixler, E. O; Kales, A; Soldatos, C. R; Kales, J. D; Healey, S (1979). "Prevalence of sleep disorders in the Los Angeles metropolitan area". American Journal of Psychiatry. 136 (10): 1257–62. doi:10.1176/ajp.136.10.1257. PMID314756.
Ohayon, Maurice M; Guilleminault, Christian; Chokroverty, Sudhansu (2010). "Sleep epidemiology 30 years later: Where are we?". Sleep Medicine. 11 (10): 961–2. doi:10.1016/j.sleep.2010.10.001. PMID21084223.
Bixler, E. O; Kales, A; Soldatos, C. R; Kales, J. D; Healey, S (1979). "Prevalence of sleep disorders in the Los Angeles metropolitan area". American Journal of Psychiatry. 136 (10): 1257–62. doi:10.1176/ajp.136.10.1257. PMID314756.
Ohayon, Maurice M; Guilleminault, Christian; Chokroverty, Sudhansu (2010). "Sleep epidemiology 30 years later: Where are we?". Sleep Medicine. 11 (10): 961–2. doi:10.1016/j.sleep.2010.10.001. PMID21084223.