Baranetskij, Y. O., Kalenyuk, P. I., & Kolyasa, L. I. (2018). Spectral properties of nonself-adjoint nonlocal boundary-value problems for the operator of differentiation of even order. Ukrains’kyi Matematychnyi Zhurnal, 70(6), 739-751. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/1592