References
- Bazley , N.W. and Kiipper , T . 1981 . Applications of Nonlinear Analysis in the Physical Sciences , London : Pitman Publishing Ltd .
- Bazley , N.W. and Weinacht , R . 1983 . Appl. Anal. Vol , 15 : 7 – 14 .
- Bazley , N.W. and Weinacht , R . 1983 . Math. Methods Appl. Sci , 15
- Berestycki , H. and Lions , P.L . 1978 . C. R. Acad. Sci Paris
- Bongers A. Dissertation
- Coffman , C.V. 1969 . J. df Analyse ma them , : 391 – 418 .
- Heinz , H.-P. 1972 . C. R. Acad. Sci , 272 Paris .
- Medeiros , L.A. 1979 . J. Math. Anal. Appl , 139
- Riinger , G. 1984 . Applied Mathematics , University of Cologne .
- Weinstein , A. and Stenger , W . 1972 . Methods of Intermediate Problems for Eigenvalues , New York : Academic Press .
- Zeidler , E. 1977/78 . Vorlesungen iiber nichtlineare Funktionalanalysis II/III , Leibzig : Teubner Texte zur Mathematik .