Late nocturnal sleep onset impairs a melatonin shower in young children. Kohyama J. Comment 2002; 23(5-6): 385-386 PubMed PMID: 12500157 Keywords: Child, Preschool, Circadian Rhythm:physiology, Humans, Japan, Melatonin:analogs & derivatives, Photic Stimulation, Photoperiod, Saliva:chemistry, Sleep:physiology, Time Factors, Urine:chemistry,. Citation ..... Read abstract Full text PDF