Santana-Aranda, Miguel Angel. “In Memoriam. Orlando Zelaya-Angel’s Contributions in Superficies Y Vacío”. Superficies y Vacío 34 (November 23, 2021). Accessed January 19, 2022. https://superficiesyvacio.smctsm.org.mx/index.php/SyV/article/view/2021_syv34_2-211123.