Sheeba V, Sharma VK, Chandrashekaran MK, Joshi A. (1999). "Persistence of eclosion rhythm in Drosophila melanogaster after 600 generations in an aperiodic environment". Die Naturwissenschaften86(9): 448–9. doi:10.1007/s001140050651. PMID 10501695.
Guyomarc'h C, Lumineau S, Richard JP. (1998). "Circadian rhythm of activity in Japanese quail in constant darkness: variability of clarity and possibility of selection". Chronobiology International15 (3): 219–30. doi:10.3109/07420529808998685. PMID 9653576.
Benloucif S, Guico MJ, Reid KJ, Wolfe LF, L'hermite-Balériaux M, Zee PC (2005). "Stability of melatonin and temperature as circadian phase markers and their relation to sleep times in humans". J Biol Rhythms20 (2): 178–88. doi:10.1177/0748730404273983.PMID 15834114.
Newman LA, Walker MT, Brown RL, Cronin TW, Robinson PR (2003). "Melanopsin forms a functional short-wavelength photopigment". Biochemistry42 (44): 12734–8.doi:10.1021/bi035418z. PMID 14596587.
Figueiro MG, Rea MS (2010). "Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students". Neuro Endocrinology Letters31 (1): 4. PMID 20150866.
Scheer FA, Wright KP, Kronauer RE, Czeisler CA (2007). "Plasticity of the intrinsic period of the human circadian timing system". PLos ONE 2 (1): e721. doi: 10.1371/journal.pone.0000721. PMID 17684566.
Recht, LD. Lew, RA. Schwartz, WJ. (1995). “Baseball teams beaten by jet lag”. Nature377: 583. PMID 7566168