Ortíz-Ávila, Elsa. “Sociodemographic Strata and Patterns Related to the First Union and First Motherhood in Mexico, 2018”. Población y Salud en Mesoamérica 18, no. 1 (June 30, 2020). Accessed January 19, 2022. https://revistas.ucr.ac.cr/index.php/psm/article/view/40350.