@article{IVM_1983_5_a13,
     author = {M. A. Zaretskaya},
     title = {The spectrum of a~class of differential operators},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {76--78},
     publisher = {mathdoc},
     number = {5},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1983_5_a13/}
}