@Book{Winkler1933,
author  = "Winkler, Ernst",
title   = "Die Unbestimmtheitstelle der ausgearteten hypergeometrischen Differentialgleichung",
year    = "1933",
address = "München",
series  = "Sitzungsberichte",
volume  = "1933,15",
url     = "https://publikationen.badw.de/en/003383411",
}