@article{RM_1974_29_5_a12,
     author = {V. A. Kazhan},
     title = {The completeness of the system of eigen- and associated functions of an elliptic operator in~$R^n$},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     year = {1974},
     volume = {29},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1974_29_5_a12/}
}