Belyaev, A.Yu. and Yushmanov, I.O., A variational principle for problems of steady-state ground water flow with a free surface, Fluid Dyn., 2015, vol. 50, no. 4, pp. 543–557.
Girinskii, N.K., Some issues of groundwater dynamics, Gidrogeol. Inzh. Geol., 1947, no. 9, pp. 27–32.
Ladyzhenskaya, O.A., Solonnikov, V.A., and Ural’tseva, N.N., Lineinye i kvazilineinye uravneniya parabolicheskogo tipa (Linear and Quasilinear Equations of Parabolic Type), Moscow: Nauka, 1967.
Ladyzhenskaya, O.A. and Ural’tseva, N.N., Lineinye i nelineinye uravneniya ellipticheskogo tipa (Linear and Nonlinear Equations of Elliptic Type), Moscow: Nauka, 1973.
Mironenko, V.A. and Serdyukov, L.I., Processing pumping test data for a two-layer bed, Razved. Okhr. Nedr, 1968, no. 10, pp. 34–38.
Myatiev, A.N., Confined system of groundwater and wells, Izv. Akad. Nauk SSSR. Otdel. Tekhn. Nauk., 1947, no. 9, pp. 1069–1088.
Shestakov, V.M., Teoreticheskie osnovy otsenki podpora, vodoponizheniya i drenazha (Theoretical Principles of Evaluating Damming, Drawdown, and Draining), Moscow: Mosk. Gos. Univ., 1965.
Alt, H.W., Strömungen durch inhomogene poröse medien mit freiem rand, J. reine angew. Math., 1979, no. 305, pp. 89–115.
Baiocchi, C. and Friedman, A., A filtration problem in a porous medium with variable permeability, Ann. Mat. Pura Appl., 1977, no. 114, pp. 377–393.
Bear, J., Hydraulics of Groundwater, McGraw Series in Water Resources and Environment Engineering, New York: McGraw-Hill Inc, 1979.
Beliaev, A.Yu., Solvability of free boundary problems for steady groundwater flow, Eur. J. Appl. Math., 2015, vol. 26, no. 6, pp. 821–847.
Chipot, M., Variational inequalities and flow through porous media, Appl. Math. Sci. Ser. 52, New York: Springer, 1984.
Torelli, A., On a free boundary value problem connected with a non steady filtration phenomenon, Annali della Scuola Norm. Sup. di Pisa, 1977, vol. 4, no. 4, pp. 33–59.