@article{DE_1970_6_1_a19,
     author = {A. M. Nakhushev},
     title = {Methods of stating well-posed problems for second order linear hyperbolic equations on the plane},
     journal = {Differencialʹnye uravneni\^a},
     pages = {192--195},
     publisher = {mathdoc},
     volume = {6},
     number = {1},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1970_6_1_a19/}
}