“Management system for the commercialization and post-sale of private blackboard services in the Territorial Division ETECSA Las Tunas” (2022) Opuntia Brava, 14(3), pp. 246–261. Available at: https://opuntiabrava.ult.edu.cu/index.php/opuntiabrava/article/view/1395 (Accessed: 29 October 2026).