Kharibegashvili, S. S., and B. G. Midodashvili. 2022. “Boundary-Value Problem for a Class of Nonlinear Systems of Partial Differential Equations of Higher Orders”. Ukrains’kyi Matematychnyi Zhurnal 74 (6), 856 -68. https://doi.org/10.37863/umzh.v74i6.6968.