David Woodward: Medieval Mappaemundi. In: The history of cartography. Vol. 1: Cartography in prehistoric, ancient, and medieval Europe and the Mediterranean. Chicago 1987. S. 321:

	David Woodward: Medieval Mappaemundi. In: The history of cartography. Vol. 1: Cartography in prehistoric, ancient, and medieval Europe and the Mediterranean. Chicago 1987. S. 321: