@article{ZNSL_1971_22_a4,
     author = {A. K. Kitover},
     title = {Spectral properties of unitary operators in~$C$},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {47--64},
     publisher = {mathdoc},
     volume = {22},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_22_a4/}
}