(en) Roberta J. Magnusson, Water Technology in the Middle Ages: Cities, Monasteries, and Waterworks after the Roman Empire, JHU Press, (ISBN978-0-8018-7283-9, lire en ligne), p. 155
(en) Benjamin Arnold, Princes and Territories in Medieval Germany, Cambridge University Press, (ISBN978-0-521-52148-2, lire en ligne), p. 77