Colón, Alegría. “F. OTTO, J.M. SONGEL - Frei Otto. Conversaciones Con Juan Maria Songel”. ZARCH. Journal of interdisciplinary studies in Architecture and Urbanism, no. 11 (December 5, 2018): 210. Accessed January 23, 2026. https://papiro.unizar.es/ojs/index.php/zarch/article/view/3217.