@article{DAN_1963_148_5_a4,
     author = {A. A. Dezin},
     title = {The simplest solvable extensions of ultrahyperbolic and pseudoparabolic operators},
     journal = {Doklady Akademii Nauk},
     pages = {1013--1016},
     publisher = {mathdoc},
     volume = {148},
     number = {5},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_148_5_a4/}
}