@article{DAN_1984_278_4_a13,
     author = {D. V. Yakubovich},
     title = {Conditions for unicellularity of weighted shift operators},
     journal = {Doklady Akademii Nauk},
     pages = {821--824},
     year = {1984},
     volume = {278},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1984_278_4_a13/}
}