Sapagovas, Mifodijus, Kristina Pupalaigė, Regimantas Čiupaila, and Tadas Meškauskas. “On the Spectrum Structure for One Difference Eigenvalue Problem With Nonlocal Boundary Conditions”. Mathematical Modelling and Analysis 28, no. 3 (September 4, 2023): 522–541. Accessed September 1, 2024. https://journals.vilniustech.lt/index.php/MMA/article/view/17503.