Barannyk, T. A., Barannyk, A. F., & Yuryk, I. I. (2017). Exact solutions of the nonliear equation $u_{tt} = = a(t) uu_{xx} + b(t) u_x^2 + c(t) u $. Ukrains’kyi Matematychnyi Zhurnal, 69(9), 1180-1186. https://umj.imath.kiev.ua/index.php/umj/article/view/1768