ČIUPAILA, R.; JESEVIČIŪTĖ, Ž.; SAPAGOVAS, M. On the Eigenvalue Problem for One-Dimensional Differential Operator with Nonlocal Integral Condition. Nonlinear Analysis: Modelling and Control, [S. l.], v. 9, n. 2, p. 109–116, 2004. DOI: 10.15388/NA.2004.9.2.15159. Disponível em: https://www.journals.vu.lt/nonlinear-analysis/article/view/15159. Acesso em: 11 apr. 2025.