Verezhak, A. P., V. V. Horodets’kyi, and R. I. Petryshyn. “A Problem for One Class of pseudodifferential evolutionary Equations Multipoint in the Time Variable”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 70, no. 3, Mar. 2018, pp. 337-55, https://umj.imath.kiev.ua/index.php/umj/article/view/1560.