@article{MZM_1981_30_3_a5,
     author = {A. A. Shkalikov},
     title = {Property of the eigenvectors of quadratic operator pencils of being a basis},
     journal = {Matemati\v{c}eskie zametki},
     pages = {371--385},
     publisher = {mathdoc},
     volume = {30},
     number = {3},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1981_30_3_a5/}
}