(意大利语). 使用|accessdate=需要含有|url= (帮助) Pius IX. The Holy See. [2017-05-03]. (原始内容存档于2016-10-17) (英语). Pope Pius IX. New Advent. [2017-05-03]. (原始内容存档于2017-03-08)
ages), Gdańsk 2006, p. 517. K. Jasiński: Rodowód Piastów małopolskich i kujawskich, Poznań–Wrocław 2001, pp. 26–27, footnote 74. Bull of PopeGregoryIX.
M. PopeGregory XII. The Catholic Encyclopedia. New York: Robert Appleton Company. 1910 [2017-12-25]. (原始内容存档于2017-12-25) –通过New Advent (英语). Pope Benedict