Gil-Mugarza, Guillermo. “Letters and Numbers. Spanish Book Production in the Twentieth Century through the Statistical Sources”. Revista de Historia Industrial — Industrial History Review 23, no. 56 (January 18, 2018): 151–187. Accessed April 30, 2024. https://revistes.ub.edu/index.php/HistoriaIndustrial/article/view/21112.