\Bibitem{Tur60} \by P.~Tur\'an \paper Lip\'ot Fej\'er (obituary) \jour Russian Math. Surveys \yr 1960 \vol 15 \issue 4 \mathnet{http://mi.mathnet.ru//eng/rm6738} \zmath{https://zbmath.org/?q=an:0093.00907}