@article{RM_1977_32_1_a23,
     author = {Yu. V. Egorov and Ts. V. Rangelov},
     title = {A class of pseudodifferential equations, with double characteristics, that have no solution},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {32},
     number = {1},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1977_32_1_a23/}
}