@article{CMFD_2017_63_2_a6,
     author = {V. S. Rykhlov},
     title = {On multiple completeness of the root functions of ordinary differential polynomial pencil with constant coefficients},
     journal = {Contemporary Mathematics. Fundamental Directions},
     pages = {340--361},
     publisher = {mathdoc},
     volume = {63},
     number = {2},
     year = {2017},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/CMFD_2017_63_2_a6/}
}