San Martín, José, Jorge Díaz, Juan Trelles, Pedro Saona, and Eduardo Maradiegue. 2015. “Preliminary Study on Detection of Neural Tube Defects by Ultrasound”. The Peruvian Journal of Gynecology and Obstetrics 41 (1):42-44. https://doi.org/10.31403/rpgo.v41i1703.