@article{DE_1977_13_1_a20,
     author = {N. G. Sorokina},
     title = {Multidimensional generalizations of {C.~Morawetz'} theorem on the weak solvability of a system of mixed type differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {155--158},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_1_a20/}
}