Periodico Oficial del Gobierno Constitucional del Estado de Durango, August 1, 1968

Periodico Oficial del Gobierno Constitucional del Estado de Durango, August 1, 1968, Box: 45, Folder: 5. Santa Cruz Mining Company Records, 1993-19. Benson Latin American Collection, The University of Texas at Austin. https://archives.lib.utexas.edu/repositories/4/archival_objects/493463 Accessed September 26, 2026.