Wilhelm (6 July 1785 –2 July 1823 ) Due to mental illness, Wilhelm was duke in name only, with his cousin Peter, Prince-Bishop of Lübeck, acting as regent throughout his entire reign.[4]
Gerhard Schildt: Von der Restauration zur Reichsgründungszeit, in Horst-Rüdiger Jarck / Gerhard Schildt (eds.), Die Braunschweigische Landesgeschichte. Jahrtausendrückblick einer Region, Braunschweig 2000, pp. 753–766.
Bille-Hansen, A. C.; Holck, Harald, eds. (1829) [1st pub.:1801]. Kongelig Dansk Hof- og Stats-Calender for Aaret 1829[Court and State Calendar of the Kingdom of Denmark for the Year 1829](PDF). Kongelig Dansk Hof- og Statskalender (in Danish). Copenhagen: J.H. Schultz A.-S. Universitetsbogtrykkeri. pp.5, 8, 51. Retrieved 16 September 2019– via da:DIS Danmark.