@article{MZM_1975_17_4_a15,
     author = {V. A. Khatskevich},
     title = {On $J$-semiunitary operators in {Hilbertian} $J$-spaces},
     journal = {Matemati\v{c}eskie zametki},
     pages = {639--647},
     year = {1975},
     volume = {17},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1975_17_4_a15/}
}