Old University Library (Erlangen) — Photo Credit: By Akriesch 20:42, 28 June 2006 (UTC) (auch de:Benutzer:Akriesch) - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=903663
Faraday's Electromagnetic rotation experiment — ca 1821 Photo Credit: By Michael Faraday - Experimental Researches in Electricity (volume 2, plate 4), Public Domain, https://commons.wikimedia.org/w/index.php?curid=4134268
Otto III, Holy Roman Emperor — Photo Credit: By Meister der Reichenauer Schule - The Yorck Project (2002) 10.000 Meisterwerke der Malerei (DVD-ROM), distributed by DIRECTMEDIA Publishing GmbH. ISBN: 3936122202., Public Domain, https://commons.wikimedia.org/w/index.php?curid=155171
