@Book{Weier1956,
author  = "Weier, Josef",
title   = "Über Abbildungen dreidimensionaler in zweidimensionale Mannigfaltigkeiten",
year    = "1956",
address = "München",
series  = "Sitzungsberichte",
volume  = "1956,9",
url     = "https://publikationen.badw.de/en/003383868",
}