@article{GDZPPN002095203, title = {Critical Point Theorems for Indefinite Functionals.}, journal = {Inventiones mathematicae}, volume = {55}, year = {1979}, pages = {241-274}, zbl = {0465.49006}, url = {http://dml.mathdoc.fr/item/GDZPPN002095203} }
Benci, Vieri; Rabinowitz, Paul H. Critical Point Theorems for Indefinite Functionals.. Inventiones mathematicae, Tome 55 (1979) pp. 241-274. http://gdmltest.u-ga.fr/item/GDZPPN002095203/