@Book{Gümbel1894,
author  = "Gümbel, Carl Wilhelm von",
title   = "Die Amberger Eisenerzformation",
year    = "1894",
address = "München",
series  = "Sitzungsberichte",
volume  = "1893,14",
url     = "https://publikationen.badw.de/en/003392643",
}