@article{MZM_2020_108_4_a1,
     author = {A. G. Baskakov and D. B. Didenko},
     title = {Spectral {Analysis} of {Operator} {Polynomials} and {Second-Order} {Differential} {Operators}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {490--506},
     publisher = {mathdoc},
     volume = {108},
     number = {4},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2020_108_4_a1/}
}