@article{DE_1975_11_1_a14,
     author = {V. I. Pa\v{s}kovskii},
     title = {Connected operators and boundary value problems of hyperbolic and degenerate hyperbolic partial differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {127--136},
     publisher = {mathdoc},
     volume = {11},
     number = {1},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_1_a14/}
}