Underhill, Frank H., author
Duke University Press, 1956
Buku Teks
Cowen, Zelman, author
North-Western University Press, 1965
Buku Teks
Mansergh, Nicholas, author
Royal Institute Of International Affair, 1948
Buku Teks
Millar, T.B.
Sydney University Press, 1967
Buku Teks
Digby, Margaret, author
Basil Blackwell , 1956
Buku Teks