@Book{Baumann1958,
author  = "Baumann, Richard",
title   = "Untersuchungen über den Darbouxschen Flächenkranz von Quasi-Rückungsflächen",
year    = "1958",
address = "München",
series  = "Sitzungsberichte",
volume  = "1957,4",
url     = "https://publikationen.badw.de/en/003383956",
}