@article{ISU_2019_19_2_a1,
     author = {V. S. Rykhlov},
     title = {Multiple completeness of the root functions of the pencils of differential operators with constant coefficients and splitting boundary conditions},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {134--151},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2019_19_2_a1/}
}