1. P. Ya. Polubarinova-Kochina, Theory of Groundwater Movement (Nauka, Moscow, 1977) [in Russian].
2. O. V. Rudenko and S. I. Soluyan, Theoretical Foundations of Nonlinear Acoustics (Nauka, Moscow, 1975) [in Russian].
3. T. D. Dzhuraev, Boundary Value Problems for Equations of Mixed and Mixed-Composite Type (Fan, Tashkent, 1979) [in Russian].
4. M. S. Salakhitdinov, Equations of Mixed-Composite Type (Fan, Tashkent, 1974) [in Russian].
5. N. I. Ionkin, ‘‘The solution of a certain boundary value problem of the theory of heat conduction with a nonclassical boundary condition,’’ Differ. Uravn. 13, 294–304 (1977).