Maikov, A.R. “On Approximate Open Boundary Conditions for the Wave Equation and the Klein-Gordon Equation”. Numerical Methods and Programming (Vychislitel’nye Metody i Programmirovanie) 6, no. 6 (November 21, 2005): 290–303. Accessed April 29, 2024. https://en.num-meth.ru/index.php/journal/article/view/172.