Robert, Charles (1888). "Double Mouton d'Or - Du Chapitre de Cambrai" [Double Gold Lamb - The Chapter of Cambrai] (PDF). Revue Numismatique. 3 (in French). 6: 78. Retrieved 1 November 2023.
Robert, Charles (1888). "Double Mouton d'Or - Du Chapitre de Cambrai" [Double Gold Lamb - The Chapter of Cambrai] (PDF). Revue Numismatique. 3 (in French). 6: 79. Retrieved 1 November 2023.