Paukštaitė, Gailė, and Artūras Štikonas. “Generalized Green’s Functions for Second-Order Discrete Boundary-Value Problems With Nonlocal Boundary Conditions”. Lietuvos matematikos rinkinys 53, no. A (December 22, 2012): 96–101. Accessed April 26, 2025. https://journals.vu.lt./LMR/article/view/14884.