@article{BGUMI_2019_1_a3,
     author = {A. S. Vaidzelevich},
     title = {On spectra of upper {Sergeev} frequencies of linear differential equations},
     journal = {Journal of the Belarusian State University. Mathematics and Informatics},
     pages = {28--32},
     year = {2019},
     volume = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/BGUMI_2019_1_a3/}
}