@article{DAN_1990_310_1_a4,
     author = {F. G. Maksudov and A. M. Magerramov and M. Z. Mamedov},
     title = {Spectral analysis of pencils of differential operators of special},
     journal = {Doklady Akademii Nauk},
     pages = {24--28},
     publisher = {mathdoc},
     volume = {310},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1990_310_1_a4/}
}