Štikonas, Artūras. “Investigation of Characteristic Curve for sturm–liouville Problem With Nonlocal Boundary Conditions on Torus”. Mathematical Modelling and Analysis 16, no. 1 (April 8, 2011): 1-22. Accessed December 22, 2024. https://jeelm.vgtu.lt/index.php/MMA/article/view/5503.