SharkovskyO. M. “Coexistence of Cycles of а Continuous Mapping of the Line into Itself”. Ukrains’kyi Matematychnyi Zhurnal 76, no. 1 (February 2, 2024): 5 - 16. Accessed December 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8026.