Mack Smith, Denis (1994). Mazzini. Yale University Press. hlm. 11–12.
bib-bvb.de
mdz10.bib-bvb.de
(Jerman) Hans Lulfing, Baedecker, KarlDiarsipkan 2018-09-16 di Wayback Machine., Neue Deutsche Biographie (NDB). Band 1, Duncker & Humblot, Berlin 1953, p. 516 f.
dhm.de
Die Reichsgründung 1871 (The Foundation of the Empire, 1871), Lebendiges virtuelles Museum Online, accessed 2008-12-22. German text translated: [...] on the wishes of Wilhelm I, on the 170th anniversary of the elevation of the House of Brandenburg to princely status on 18 January 1701, the assembled German princes and high military officials proclaimed Wilhelm I as German Emperor in the Hall of Mirrors at the Versailles Palace.
(Jerman) Hans Lulfing, Baedecker, KarlDiarsipkan 2018-09-16 di Wayback Machine., Neue Deutsche Biographie (NDB). Band 1, Duncker & Humblot, Berlin 1953, p. 516 f.