@article{PORMA_1972__31_4_115181,
     author = {Cesar, M.O. and Lopes, F. and Oliva, W.M.},
     title = {The {La} {Salle} invariance principle for multidimensional dynamical systems},
     journal = {Portugaliae mathematica},
     pages = {215--230},
     publisher = {mathdoc},
     volume = {31},
     number = {4},
     year = {1972},
     mrnumber = {0305875},
     zbl = {0259.35004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1972__31_4_115181/}
}