Ahmad, S.; Lazer, A. C.; Paul, J. L. Elementary critical point theory and perturbations of elliptic boundary value problems at resonance. (English) Zbl 0351.35036 Indiana Univ. Math. J. 25, 933-944 (1976). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 4 ReviewsCited in 102 Documents MSC: 35J60 Nonlinear elliptic equations 26B05 Continuity and differentiation questions 35J20 Variational methods for second-order elliptic equations 35J25 Boundary value problems for second-order elliptic equations PDF BibTeX XML Cite \textit{S. Ahmad} et al., Indiana Univ. Math. J. 25, 933--944 (1976; Zbl 0351.35036) Full Text: DOI