Kreinovich, Vladik, Martine Ceberio, and Quentin Brefort. “In Category of Sets and Relations, It Is Possible to Describe Functions in Purely Category Terms”. Eurasian Mathematical Journal 6, no. 2 (June 30, 2015): 90–94. Accessed October 31, 2025. https://emj.enu.kz/index.php/main/article/view/611.