@article{MABA_1991_5_4_a6,
     author = {N. K. Ribar ska and Ts. Y. Tsachev and M. I. Krastanov},
     title = {On the {General} {Mountain} {Pass} {Principle} of {Ghoussoub-Preiss}},
     journal = {Mathematica balkanica},
     pages = {350},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/MABA_1991_5_4_a6/}
}