References
- Amann , H. 1988 . Order structures and fixed points . Preprint, Mathematisches Institute Ruhr - Universitat ,
- Appel , J. 1988 . The superposition operator in function spaces - A survey . Expo. Math , 6 : 209 – 270 .
- Carl , S. 1988 . Ein konstruktiver Existenzsatz fur Randwertprobleme elliptis- cher Differentialgleichungen zweiter ordnung mit unstetiger Nichtlinearitat . Math. Nachr , 138
- Deimling , k. 1985 . Nonlinear Functional Analysis , New York : Springer - Verlag .
- Gilbarg , D. and Trudinger , N.S. 1983 . Elliptic partial differential equations of second order , Berlin, Heidelberg, New York : Springer - Verlag .
- Heikkila , S. 1983 . On fixed points through a generalized iteration method with applications to differential and integral equations involving discontinuities . Nonlinear Analysis (to appear) ,