(EN) John France, The Crusades and the expansion of Catholic Christendom, 1000-1714, Routledge, 2005, p. 265, ISBN 978-0-415-37128-5.
«The costs of these troops and the nagging wars with Poland, which ended indecisively in 1435, bore heavily upon the cities, merchants, and knightly settlers in Prussia, with the result that the Grand Master found ever more resistance to his central and despotic control.»