@article{VUU_2023_33_1_a9,
     author = {A. Kh. Stash},
     title = {On essential values of {Sergeev's} frequencies and exponents of oscillation for solutions of a third-order linear differential periodic equation},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {141--155},
     year = {2023},
     volume = {33},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2023_33_1_a9/}
}