Norman Davies, God's Playground. A History of Poland, Vol. 1: The Origins to 1795, Vol. 2: 1795 to the Present. Oxford: Oxford University Press. ISBN 0-19-925339-0 / ISBN 0-19-925340-4(англ.)
Aleksander Gella, Development of Class Structure in Eastern Europe: Poland and Her Southern Neighbors, SUNY Press, 1998, ISBN 0-88706-833-2, Google Print, p13 (англ.)
Norman Davies, God's Playground: A History of Poland in Two Volumes, Oxford University Press, 2005, ISBN 0-19-925339-0, p.262 (англ.)