1. A. V. Bitsadze and A. A. Samarskii, “On some simple generalized linear elliptic problems,” Dokl. Akad. Nauk SSSR 185 (4), 739–740 (1969).
2. N. I. Ionkin, “Solution of a boundary-value problem in heat conduction with a nonclassical boundary condition,” Differ. Uravn. 13 (2), 294–304 (1977).
3. N. I. Ionkin, “On the stability of a problem in heat conduction with a nonclassical boundary condition,” Differ. Uravn. 15 (7), 1279–1283 (1979).
4. A. A. Samarskii, “On certain problems in the theory of differential equations,” Differ. Uravn. 16 (11), 1925–1935 (1980).
5. N. I. Yurchuk, “Mixed problem with an integral condition for certain parabolic equations,” Differ. Uravn. 22 (12), 2117–2126 (1986).