DragunovD. V., MakarovV. L., and SemberD. A. “FD-Method for Solving the Nonlinear Klein - Gordon Equation”. Ukrains’kyi Matematychnyi Zhurnal 64, no. 10 (October 25, 2012): 1394-1415. Accessed November 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2667.