1. Sobolev Spaces;Adams,1975
2. Characterizations of the ranges of some nonlinear operators and applications to boundary value problems;Brezis;Annali. Scu. norm. sup. Pisa,1978
3. Semilinear elliptic equations at resonance: higher eigenvalues and unbounded nonlinearities;De Figueiredo,1981
4. Nonlinear perturbations of a linear elliptic problem near its first eigenvalue;De Figueiredo;J. diff. Eqns,1978
5. Elliptic Partial Differential Equations of Second Order;Gilbarg,1977