Tolong jelaskan mengenai Bacaan selanjutnya dari Ludwig yang Saleh

Booker, Courtney M. Past Convictions: The Penance of Louis the Pious and the Decline of the Carolingians, University of Pennsylvania Press, 2009, ISBN 978-0-8122-4168-6

De Jong, Mayke. The Penitential State: Authority and Atonement in the Age of Louis the Pious, 814–840. New York: Cambridge University Press, 2009.

Depreux, Philippe. Prosopographie de l'entourage de Louis le Pieux (781–840). Sigmaringen: Thorbecke, 1997. A useful prosopographical overview of Louis' household, court and other subordinates.

Eichler, Daniel. Fränkische Reichsversammlungen unter Ludwig dem Frommen. Hannover: Hahnsche Buchhandlung, 2007 (Monumenta Germaniae Historica Studien und Texte, 45).

Ganshof, François-Louis The Carolingians and the Frankish Monarchy. 1971.

Godman, Peter, and Roger Collins (eds.). Charlemagne's Heir: New Perspectives on the Reign of Louis the Pious (814–840). Oxford and New York: Clarendon Press, 1990.

Oman, Charles. The Dark Ages 476–918. London, 1914.