@article{IVM_1968_6_a9,
     author = {I. Z. Manevich},
     title = {Existence of periodic solutions of a~system of three differential operators},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {75--76},
     publisher = {mathdoc},
     number = {6},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1968_6_a9/}
}