V. Būda, M. Sapagovas, O. Štikonienė, and A. Štikonas, “M-matrices and one-dimensional discrete Sturm–Liouville problems with nonlocal boundary conditions”, NAMC, vol. 30, no. 4, pp. 704–731, Jul. 2025, doi: 10.15388/namc.2025.30.42210.