@article{MZ_1992__209_2_174371,
     author = {Andrej Szulkin},
     title = {Cohomology and {Morse} theory for strongly indefinite functionals.},
     journal = {Mathematische Zeitschrift},
     pages = {375--418},
     publisher = {mathdoc},
     volume = {209},
     number = {2},
     year = {1992},
     zbl = {0735.58012},
     url = {http://geodesic.mathdoc.fr/item/MZ_1992__209_2_174371/}
}