@article{AA_1990_2_1_a4,
     author = {N. A. Karpenko},
     title = {Algebro-geometric invariants of quadratic forms},
     journal = {Algebra i analiz},
     pages = {141--162},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1990_2_1_a4/}
}