\Bibitem{Che94} \by V.~I.~Chernousov \paper The group of congruence coefficients of a canonical quadratic form and stable rationality of the $PSO$ variety \jour Mat. Zametki \yr 1994 \vol 55 \issue 4 \pages 114--119 \mathnet{http://mi.mathnet.ru/mzm2183} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=1296222} \zmath{https://zbmath.org/?q=an:0855.11019} \transl \jour Math. Notes \yr 1994 \vol 55 \issue 4 \pages 413--416 \crossref{https://doi.org/10.1007/BF02112482} \isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=A1994QE41300026}