1. On some existence theorems for semi-linear elliptic equations;Amann;Indiana Univ. Math. J.,1978
2. Characterizations of the ranges of some nonlinear operators and applications to boundary value problems;Brézis;Annali Scu. norm. sup. Pisa Serie IV,1978
3. On an elliptic boundary value problem not in divergence form;Các;Proc. Am. math. Soc.,1983
4. Solvability of the Dirichlet problem in H2,p(Ω) for a class of linear second order elliptic partial differential equations;Chicco;Boll. Un. mat. ital.,1971
5. Invariant criteria for existence of solutions to second order quasilinear elliptic equations;Kazdan;Communs pure appl. Math.,1978