Tosh, John
Longman , 1991
Buku Teks SO
Tawney, R.H.
George Allen and Unwin, 1952
Buku Teks
hapus4
China Renmin University Press, 2015
eBooks
Bailey, Thomas Andrew, 1902-1983
D.C. Healt, 1987
Buku Teks
Herget, James E.
Texas: Rice University Press, 1990,
Buku Referensi