Xohua-Chacón, José Antonio, Edgard Iván Benítez-Guerrero, and Carmen Mezura-Godoy. “A Tangible System for Learning Relational Algebra”. Revista Colombiana de Computación 19, no. 1 (June 1, 2018): 39–55. Accessed November 14, 2026. https://revistas.unab.edu.co/rcc/article/view/3228.