Maternal Folic Acid Intake and Methylation Status of Genes Associated with Ventricular Septal Defects in Children: Case–Control Study oleh Sandra M. González-Peña, Geovana Calvo-Anguiano, Laura E. Martínez-de-Villarreal, Patricia R. Ancer-Rodríguez, José J. Lugo-Trampe, Donato Saldivar-Rodríguez, María D. Hernández-Almaguer, Melissa Calzada-Dávila, Ligia S. Guerrero-Orjuela, Luis D. Campos-Acevedo