@Book{Schoenberg1950,
author  = "Schoenberg, Erich",
title   = "Der Libellensextant für gleiche Höhen",
year    = "1950",
address = "München",
series  = "Sitzungsberichte",
volume  = "1949,3.",
url     = "https://publikationen.badw.de/de/003383622",
}