Urquidi, Víctor, and Sofía Méndez Villarreal. "Importancia Económica de la Zona Fronteriza del Norte de México." (Versión preliminar) Conference on Contemporary Dilemmas of the Mexican-United States Border, San Antonio, 1975 April 14-18

Urquidi, Víctor, and Sofía Méndez Villarreal. "Importancia Económica de la Zona Fronteriza del Norte de México." (Versión preliminar) Conference on Contemporary Dilemmas of the Mexican-United States Border, San Antonio, 1975 April 14-18, Box: 211, Folder: 1. Julian Samora Papers, 24426265. Benson Latin American Collection, The University of Texas at Austin. https://archives.lib.utexas.edu/repositories/4/archival_objects/390028 Accessed September 26, 2026.