@article{DE_1999_35_3_a6,
     author = {I. Birindelli and E. Mitidieri and G. Sweers},
     title = {Existence of the principal eigenvalue for cooperative elliptic systems in a general domain},
     journal = {Differencialʹnye uravneni\^a},
     pages = {325--333},
     publisher = {mathdoc},
     volume = {35},
     number = {3},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_3_a6/}
}