@article{RM_1961_16_5_a5,
     author = {R. S. Ismagilov},
     title = {Functions of {Hermitian} operators},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     year = {1961},
     volume = {16},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1961_16_5_a5/}
}