@article{MZM_2019_105_4_a13,
     author = {D. M. Polyakov},
     title = {On the {Spectral} {Characteristics} of {Non-Self-Adjoint} {Fourth-Order} {Operators} with {Matrix} {Coefficients}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {637--642},
     publisher = {mathdoc},
     volume = {105},
     number = {4},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2019_105_4_a13/}
}