Wolfgang Van Emden, Kingship in the Old French epic of revolt, Kings and Kingship in Medieval Europe, King's College London Medieval Studies, 10, London, King's College, 1993 : p. 305 - 350
With particular reference to the chansons de geste Girart de Roussillon, Raoul de Cambrai, Renaud de Montauban , Ogier de Danemarche , and Girart de Vienne