^F.C. Berkenvelder. De handel en de Hanze. Zwolle 750 jaar stad. Waanders. 1980 [17 March 2007]. (原始內容存檔於2007-09-28) (荷蘭語). De stedelijke geldmiddelen, het nationaal inkomen zouden wij nu zeggen, die in 1402 nog 6.000 gulden bedroegen waren in 1450 bijna verzesvoudigd tot 34.000 gulden. (Translated: The city's financial resources, the national income as we would now call it, which were 6,000 guilders in 1402, had by 1450 multiplied by six to 34,000 guilders.)
^陳奕伸. 《荷蘭旅遊隨身書:在麵包店遇見荷蘭女王》. 台北縣中和市: 棋碁出版社. 2005-01-07. ISBN 9572997742.