title: Time-domain system for assessing variation in heart rate.
authors.forename: V L
authors.initials: VL
authors.lastname: Schechtman
authors.forename: K A
authors.initials: KA
authors.lastname: Kluge
authors.forename: R M
authors.initials: RM
authors.lastname: Harper
mesh_terms: D004562:Electrocardiography / Q000379:methods*; D005583:Fourier Analysis; D006339:Heart Rate; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012894:Sleep Stages; D013997:Time Factors