@article{FAA_1982_16_3_a16,
     author = {M. M. Malamud},
     title = {Necessary conditions for the existence of a transformation operator for higher-order equations},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {74--75},
     publisher = {mathdoc},
     volume = {16},
     number = {3},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1982_16_3_a16/}
}