title: Neonatal smiling in REM states, IV. Premature study.
mesh_terms: D001034:Apgar Score; D001724:Birth Weight; D002652:Child Behavior; D005149:Facial Expression; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D012895:Sleep, REM