@article{MZM_2013_94_1_a4,
     author = {J. Ben Amara and A. A. Vladimirov and A. A. Shkalikov},
     title = {Spectral and {Oscillatory} {Properties} of a {Linear} {Pencil} of {Fourth-Order} {Differential} {Operators}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {55--67},
     publisher = {mathdoc},
     volume = {94},
     number = {1},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2013_94_1_a4/}
}