@article{GDZPPN00220861X,
title = {Critical point theory with symmetries.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {416},
year = {1991},
pages = {1-30},
zbl = {0722.58011},
url = {http://dml.mathdoc.fr/item/GDZPPN00220861X}
}
Puppe, Dieter; Clapp, Mónica. Critical point theory with symmetries.. Journal für die reine und angewandte Mathematik, Tome 416 (1991) pp. 1-30. http://gdmltest.u-ga.fr/item/GDZPPN00220861X/