1. Nakhushev, A.M., Loaded equations and applications, Differ. Uravn., 1983, vol. 19, no. 1, pp. 86–94.
2. Budak, V.M. and Iskenderov, A.D., On a class of inverse boundary value
problems with unknowns, Dokl. Akad. Nauk SSSR,
1967, vol. 176, no. 1, pp. 20–23.
3. Kaziev, V.M., The Tricomi problem for the loaded Lavrent’ev–Bitsadze
equation, Differ. Uravn., 1979, vol. 15, no. 1,
pp. 173–175.
4. Krall, A.M., The development of general differential and general differential
boundary systems, Rock. Mt. J. Math., 1975, vol. 5,
no. 4, pp. 493–542.
5. Barenblat, G.I., Zheltov, Yu.P., and Kochina, I.N., On the basic concepts of
the theory of filtration of homogeneous fluids in fractured rocks, Prikl.
Mat. Mekh., 1960, vol. 25, no. 5, pp. 852–864.