@article{DAN_1967_174_2_a7,
     author = {A. M. Perelomov and V. S. Popov},
     title = {Casimir operators for the classical groups},
     journal = {Doklady Akademii Nauk},
     pages = {287--290},
     publisher = {mathdoc},
     volume = {174},
     number = {2},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_174_2_a7/}
}