@article{MZM_1969_5_4_a8,
     author = {M. S. Brodskii},
     title = {On the rank of a spectral function},
     journal = {Matemati\v{c}eskie zametki},
     pages = {457--460},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1969_5_4_a8/}
}