Rosamond McKitterick, The Frankish Kingdoms under the Carolingians, (Pearson Education Limited, 1999), 258.

John VIII, Pierre Riche, The Papacy: Gaius-Proxies, Vol.
2, ed.
Philippe Levillain, (Routledge, 2002), 837.

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (
1911). "
Louis II.
of France".
Encyclopædia Britannica.
17 (11th ed.).
Cambridge University Press.
p. 34.
Rosamond McKitterick, The Frankish Kingdoms under the Carolingians, (Pearson Education Limited, 1999), 258.
John VIII, Pierre Riche, The Papacy: Gaius-Proxies, Vol. 2, ed. Philippe Levillain, (Routledge, 2002), 837.
 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Louis II. of France". Encyclopædia Britannica. 17 (11th ed.). Cambridge University Press. p. 34.
Louis the Stammerer