Brzychczy, S., A. K. Prykarpatsky, and V. G. Samoilenko. “Finite-Dimensional Reductions of Conservative Dynamical Systems and Numerical Analysis. I”. Ukrains’kyi Matematychnyi Zhurnal 53, no. 2 (February 25, 2001): 220–228. Accessed April 14, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4237.