@Book{Kapfer1927,
author  = "Kapfer, Josephina",
title   = "Über isogonale Flächen 2. Art",
year    = "1927",
address = "München",
series  = "Sitzungsberichte",
volume  = "1927,9",
url     = "https://publikationen.badw.de/en/003390907",
}