@article{MZM_2000_67_3_a5,
     author = {I. M. Nabiev},
     title = {Multiplicities and relative position of eigenvalues of a~quadratic pencil of {Sturm--Liouville} operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {369--381},
     publisher = {mathdoc},
     volume = {67},
     number = {3},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2000_67_3_a5/}
}