@article{DAN_1973_213_5_a1,
     author = {Yu. M. Berezanskii and G. F. Us},
     title = {On the expansion in eigenfunctions of selfadjoint operators admitting a separation of infinitely many variables},
     journal = {Doklady Akademii Nauk},
     pages = {1005--1008},
     publisher = {mathdoc},
     volume = {213},
     number = {5},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1973_213_5_a1/}
}