Barannyk, T. A., A. F. Barannyk, and I. I. Yuryk. “Generalized Separation of Variables and exact solutions of Nonlinear Equations”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 62, no. 12, Dec. 2010, pp. 1598 -09, https://umj.imath.kiev.ua/index.php/umj/article/view/2985.