Foerster,Thomas(2016).“Crossing the Alps and Crossing the Channel. The 'Empires' of Frederick I and Henry II”.Staufen and Plantagenets: Two Empires in Comparison.Bonn University Press
Gislebertus (of Mons)(2005).Chronicle of Hainaut.The Boydell Press
Bouchard,Constance Brittain(1987).Sword, Miter, and Cloister: Nobility and the Church in Burgundy, 980-1198.Cornell University Press
McKitterick, Rosamond;Abulafia, David, eds(1999).The New Cambridge Medieval History: Volume 5, C.1198-c.1300.Cambridge University Press