1. M. S. Berger, Nonlinearity and Functional Analysis, Academic Press, New York, 1977.
2. R. R. Coifman and Y. Meyer, Lavrentiev’s Curves and Conformal Mappings, Institut Mittag-Leffler, Report No. 5, 1983.
3. K. Deimling, Nonlinear Functional Analysis, Springer Verlag, Berlin, etc., 1985.
4. F. D. Gakhov, Boundary Value Problems, Pergamon Press, Oxford, etc., 1966.
5. G. M. Goluzin, Geometric Theory of Functions of a Complex Variable, Amer. Math. Soc., Providence, Rhode Island, 1969.