@Book{Liebmann1923,
author  = "Liebmann, Heinrich",
title   = "Beiträge zur Inversionsgeometrie der Kurven",
year    = "1923",
address = "München",
series  = "Sitzungsberichte",
volume  = "1923,3",
url     = "https://publikationen.badw.de/en/003399301",
}