Álvarez Alonso, Marina, Olga Río Suárez, Pilar Rodríguez-Monteverde Cantarell, and J. Miguel Barbero Sánchez. “Concrete Blocks. Analysis of UNE, ISO En Standards and Comparison With Other International Standards”. Materiales de Construcción 40, no. 220 (December 30, 1990): 37–51. Accessed May 2, 2025. https://materconstrucc.revistas.csic.es/index.php/materconstrucc/article/view/764.