ShokoohS., Afrouzi G.A. and HadjianA. 2020. On the existence of solutions of one-dimensional fourth-order equations. Ukrains’kyi Matematychnyi Zhurnal. 72, 11 (Nov. 2020), 1575-1588. DOI:https://doi.org/10.37863/umzh.v72i11.569.