Heterotopic pregnancy. Presentation of four cases. Colombia Medica, [S. l.], v. 42, n. 4, p. 518–522, 2011. DOI: 10.25100/cm.v42i4.953. Disponível em: https://colombiamedica.univalle.edu.co/index.php/comedica/article/view/953. Acesso em: 14 feb. 2026.