@article{AA_1991_3_2_a8,
     author = {V. N. Pyvovarchyk},
     title = {On the total algebraic multiplicity of the spectrum in the right half-plane for a~class of quadratic operator pencils},
     journal = {Algebra i analiz},
     pages = {223--230},
     publisher = {mathdoc},
     volume = {3},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1991_3_2_a8/}
}