@Book{Szász1917,
author  = "Szász, Otto",
title   = "Über nichtnegative trigonometrische Polynome",
year    = "1917",
address = "München",
series  = "Sitzungsberichte",
volume  = "1917,16",
url     = "https://publikationen.badw.de/de/003395579",
}