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@article{IVM_1973_5_a9, author = {V. N. Polyakov}, title = {A~multiplication theorem for the characteristic functions of linear operators}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {73--76}, publisher = {mathdoc}, number = {5}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1973_5_a9/} }
V. N. Polyakov. A~multiplication theorem for the characteristic functions of linear operators. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 5 (1973), pp. 73-76. http://geodesic.mathdoc.fr/item/IVM_1973_5_a9/