Bosau, p. 304; David Abulafia, The Boundless Sea: a human history of the oceans (Oxford, 2019), p. 424.

Peter Johanek, ‘Seigneurial Power and the Development of Towns in the Holy Roman Empire’, in Anngret Simms and Howard B. Clarke (eds.), Lords and Towns in Medieval Europe: the European Historic Towns Atlas Project (London, 2015) p. 142.