@article{MZM_1995_58_6_a18,
     author = {A. A. Shkalikov},
     title = {On~the essential spectrum of matrix operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {945--949},
     publisher = {mathdoc},
     volume = {58},
     number = {6},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1995_58_6_a18/}
}