Calvo Calvo, Ángel. “Telefonica Takes Command. Private Monopoly, Automatization and Expansion of the Telephone in Spain, 1924-1945”. Revista de Historia Industrial — Industrial History Review 15, no. 32 (July 26, 2017): 69–98. Accessed July 31, 2024. https://revistes.ub.edu/index.php/HistoriaIndustrial/article/view/19677.