Horodets’kyiV. V., and MartynyukO. V. 2014. “Nonlocal Problem Multipoint in Time for the Evolutionary Equations With Pseudo-Bessel Operators With Variable Symbols”. Ukrains’kyi Matematychnyi Zhurnal 66 (2), 159–175. http://umj.imath.kiev.ua/index.php/umj/article/view/2120.