@article{MZM_2002_72_2_a16,
     author = {A. S. Kostenko},
     title = {On the {Defect} {Index} of {Quadratic} {Self-Adjoint} {Operator} {Pencils}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {315--320},
     publisher = {mathdoc},
     volume = {72},
     number = {2},
     year = {2002},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2002_72_2_a16/}
}