@article{MZM_1997_62_6_a14,
     author = {G. G. Amosov and A. V. Bulinski},
     title = {The {Powers{\textendash}Arveson} index for quasifree dynamical semigroups},
     journal = {Matemati\v{c}eskie zametki},
     pages = {933--936},
     year = {1997},
     volume = {62},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1997_62_6_a14/}
}