Ruiz Simón, Esther. “Historical Views of Solidarity the Twentieth Century: Development and International Cooperation through Manos Unidas Newsletters”. HUMAN REVIEW. International Humanities Review / Revista Internacional de Humanidades 15, no. 2 (December 21, 2022): 1–8. Accessed July 18, 2024. http://journals.eagora.org/revHUMAN/article/view/4223.