@Book{Spiegel1867,
author  = "Spiegel, Friedrich von",
title   = "Ueber das Leben Zarathustra's",
year    = "1867",
address = "München",
series  = "Sitzungsberichte",
volume  = "1867,1,1",
url     = "https://publikationen.badw.de/de/003393144",
}