@article{KUTGS_1983_15_a7,
     author = {V. G. Kopp},
     title = {Invariants of groups of motions in {pseudo-Euclidean} spaces},
     journal = {Trudy Geometricheskogo Seminara},
     pages = {50--57},
     publisher = {mathdoc},
     volume = {15},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUTGS_1983_15_a7/}
}