Cortés-Yepes, Hernán. “Doppler Ultrasound Screening During the First Trimester of Pregnancy for Preeclampsia: A Cohort Study. Bogotá, Colombia 2007 -2008”. Revista Colombiana de Obstetricia y Ginecología 60, no. 4 (December 20, 2009): 328–333. Accessed July 22, 2024. https://revista.fecolsog.org/index.php/rcog/article/view/315.