Bowen, John R., author
Cambridge Uiversity Press, 2003
Buku Teks
Kiikeri, Markku
Kluwer Academic Publishers, 2001
Buku Teks
Tawney, R.H., author
George Allen and Unwin, 1952
Buku Teks
Wu, Xiaoyun, author
China Renmin University Press, 2015
eBooks
Zelermyer, William
Prentice-Hall, 1960
Buku Teks