Sepulveda Waldo, Campana Claudio, Carstens Eduardo, Rodriguez Jorge
Fetal Medicine Center, Department of Obstetrics and Gynecology, Clinica Las Condes, Santiago, Chile.
J Ultrasound Med. 2003 Aug;22(8):841-4; quiz 845-6. doi: 10.7863/jum.2003.22.8.841.