Cardiac Interbeat Interval Dynamics from Childhood to Senescence: Comparison of Conventional and new Measures based on Fractals and Chaos Theory - Pikkujämsä, SM; Mäkikallio, TH; Sourander, LB; Räihä, IJ; Puukka, P; Skyttä, J; Peng, CK; Goldberger, AL; Huikuri, HV (Circulation, 1999)