References
Normal values of M mode echocardiographic measurements of more than 2000 healthy infants and children in central Europe.
C Kampmann, C Wiethoff, A Wenzel, G Stolz, M Betancor, C Wippermann, R Huth, P Habermehl, M Knuf, T Emschermann, and H Stopfkuchen
Heart. 2000 June; 83(6): 667–672.