Samoilenko, A. M., S. M. Chuiko, and O. V. Nesmelova. 2020. “Nonlinear Boundary-Value Problems Unsolved With Respect to the Derivative”. Ukrains’kyi Matematychnyi Zhurnal 72 (8): 1106-18. https://doi.org/10.37863/umzh.v72i8.5986.