SokilB. I. “On the Application of Ateb-Functions to the Construction of a Solution of a Nonlinear Klein-Gordon Equation”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 49, no. 6, June 1997, pp. 872–877, https://umj.imath.kiev.ua/index.php/umj/article/view/5076.