VereikinaM. B., and SharkovskyO. M. “Tracing of Pseudotrajectories of Dynamical Systems and Stability of Prolongations of Orbits”. Ukrains’kyi Matematychnyi Zhurnal 49, no. 8 (August 25, 1997): 1016–1024. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5096.