Muñoz Delgado, S., Valencia, L.F., Villa R., I., Valdivieso, H. and Sánchez, A. 1990. Techography. Intrauterine localization of copper T-type devices by transabdominal sonogram. Colombia Medica. 21, 4 (Dec. 1990), 149–154. DOI:https://doi.org/10.25100/cm.v21i4.6320.