\Bibitem{Gue45} \by S.~Guelfer \paper On a property of bounded functions \jour Sb. Math. \yr 1945 \vol 58 \issue 3 \mathnet{http://mi.mathnet.ru//eng/sm6334} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=14460} \zmath{https://zbmath.org/?q=an:0063.01780}