@article{TM_1975_135_a27,
     author = {A. S. Holevo},
     title = {Mathematical problems in the theory of quantum channels},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {226--227},
     year = {1975},
     volume = {135},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1975_135_a27/}
}