ŠTIKONAS, Artūras. Investigation of characteristic curve for sturm–liouville problem with nonlocal boundary conditions on torus. Mathematical Modelling and Analysis, [S. l.], v. 16, n. 1, p. 1–22, 2011. DOI: 10.3846/13926292.2011.552260. Disponível em: https://journals.vilniustech.lt/index.php/MMA/article/view/5503. Acesso em: 9 may. 2025.