@article{FAA_1987_21_4_a15,
     author = {A. V. Rybkin},
     title = {Trace for the pair of a contraction and a unitary operator},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {85--87},
     publisher = {mathdoc},
     volume = {21},
     number = {4},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1987_21_4_a15/}
}