@article{TSP_2013_29_29_a12,
     author = {I. N. Sergeev},
     title = {Properties of characteristic frequencies of linear equations of arbitrary order},
     journal = {Trudy Seminara im. I.G. Petrovskogo},
     pages = {414--442},
     publisher = {mathdoc},
     volume = {29},
     number = {29},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TSP_2013_29_29_a12/}
}