@article{IVM_1977_9_a6,
     author = {N. M. Kostenko},
     title = {A~transformation operator},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {43--47},
     publisher = {mathdoc},
     number = {9},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1977_9_a6/}
}