@article{AIHPC_1989__6_5_321_0,
     author = {Ghoussoub, N. and Preiss, D.},
     title = {A general mountain pass principle for locating and classifying critical points},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {321--330},
     publisher = {Gauthier-Villars},
     volume = {6},
     number = {5},
     year = {1989},
     mrnumber = {1030853},
     zbl = {0711.58008},
     language = {en},
     url = {http://www.numdam.org/item/AIHPC_1989__6_5_321_0/}
}