\Bibitem{Gol50} \by Yu.~A.~Gol'fand \paper Metaspecial groups \jour Sb. Math. \yr 1950 \vol 69 \issue 2 \mathnet{http://mi.mathnet.ru//eng/sm5915} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=38973} \zmath{https://zbmath.org/?q=an:0039.25302}