\Bibitem{Sup59} \by D.~A.~Suprunenko \paper On~real linear nilpotent groups \jour Sb. Math. \yr 1959 \vol 91 \issue 3 \mathnet{http://mi.mathnet.ru//eng/sm4924} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=110755} \zmath{https://zbmath.org/?q=an:0087.02203}