@article{GDZPPN002439999,
title = {Cohomology and Morse theory for strongly indefinite functionals.},
journal = {Mathematische Zeitschrift},
volume = {209},
year = {1992},
pages = {375-418},
zbl = {0735.58012},
url = {http://dml.mathdoc.fr/item/GDZPPN002439999}
}
Szulkin, Andrej. Cohomology and Morse theory for strongly indefinite functionals.. Mathematische Zeitschrift, Tome 209 (1992) pp. 375-418. http://gdmltest.u-ga.fr/item/GDZPPN002439999/