Archer SN, Robilliard DL, Skene DJ, Smits M, Williams A, Arendt J, von Schantz M. A length polymorphism in the circadian clock gene Per3 is linked to delayed sleep phase syndrome and extreme diurnal preference. Sleep. June 2003, 26 (4): 413–5. PMID 12841365. doi:10.1093/sleep/26.4.413.
Archer SN, Robilliard DL, Skene DJ, Smits M, Williams A, Arendt J, von Schantz M. A length polymorphism in the circadian clock gene Per3 is linked to delayed sleep phase syndrome and extreme diurnal preference. Sleep. June 2003, 26 (4): 413–5. PMID 12841365. doi:10.1093/sleep/26.4.413.