Saggs, H. W. F.
New American Library, 1968
Buku Teks
Ferguson, Wallace K.
Houghton Miffiln, 1942
Buku Klasik
Yudha Akbar, author
2007
Artikel Jurnal
Huntington, Ellsworth, author
John Wiley & Sons, 1945
Buku Teks
Toynbee, Arnold J., author
Oxford University Press , 1957
Buku Teks