1. Pontificia Universidad Javeriana; Department of Clinical Epidemiology and Biostatistics, Faculty of Medicine; Cr. 7 #40-62, 2nd floor Bogota DC Colombia
2. University of Cambridge; Department of Obstetrics and Gynecology; Cambridge UK
3. University of Vermont; Division of Neonatal-Perinatal Medicine; Fletcher Allen Health Care, Smith 552A 111 Colchester Avenue Burlington Vermont USA 05401