@article{AA_1990_2_1_a7,
     author = {M. Szyjewski},
     title = {The fifth invariant of quadratic forms},
     journal = {Algebra i analiz},
     pages = {213--234},
     publisher = {mathdoc},
     volume = {2},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_1990_2_1_a7/}
}