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.
https://umj.imath.kiev.ua/index.php/umj/article/view/1592