The G619A Aa-nat gene polymorphism does not contribute to sleep time variation in the Brazilian population - Pereira, Danyella Silva; Pedrazzoli Neto, Mário; Koike, Bruna Del Vechio; Louzada, Fernando Mazzili; Benedito-Silva, Ana Amélia; Lopez, Alberto Remesar; Tufik, Sergio (Behavior Genetics, 2007)