@Book{Gruber1902,
author  = "Gruber, K.",
title   = "Der Schwefel- und Magnetkiesbergbau am Silberberge bei Bodenmais",
year    = "1902",
address = "München",
series  = "Abhandlungen",
volume  = "Bd. 21, Abth. 2 = [4]",
url     = "https://publikationen.badw.de/en/003071166",
}