Sapagovas, Mifodijus, Artūras Štikonas, and Olga Štikonienė. “Chebyshev Iteration for the Problem With Nonlocal Boundary Condition”. Lietuvos matematikos rinkinys 44, no. spec. (December 17, 2004): 665–669. Accessed November 6, 2025. https://www.zurnalai.vu.lt/LMR/article/view/15313.