@article{DAN_1969_187_6_a5,
     author = {Yu. V. Egorov},
     title = {The conditions of solvability of pseudodifferential equations},
     journal = {Doklady Akademii Nauk},
     pages = {1232--1234},
     publisher = {mathdoc},
     volume = {187},
     number = {6},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_187_6_a5/}
}