1. S. K. Godunov, L. V. Zabrodin, M. Ya. Ivanov, et al., Numerical Solution of Multidimensional Problems of Gas Dynamics [in Russian], Nauka, Moscow (1976).
2. S. K. Godunov, E. I. Romenskiî, and G. A. Chumakov, ?Constructing difference grids in involved domains by means of quasiconformal maps,? Trudy Inst. Mat. (Novosibirsk),18, 75?84 (1990).
3. M. Berge, Geometry. Vol. 1, [Russian translation], Mir, Moscow (1984).
4. M. Berge, Geometry. Vol. 2 [Russian translation], Mir, Moscow (1984).
5. M. A. Lavrent'ev and B. V. Shabat, Methods of the Theory of Functions of a Complex Variable [in Russian], OGIZ, Moscow (1958).