BerezanskyY. M., MitropolskiyY. A., & Shkhanukov-LafishevM. K. (1995). On a nonlocal problem for a parabolic equation. Ukrains’kyi Matematychnyi Zhurnal, 47(6), 790–800. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/5473