Brown, John Mason
Harper & Row, 1965
Buku Teks
McCullough, Helen Craig
Princeton University Press, 1980
Buku Teks
Times Books, 1991
Buku Referensi
Balfour, Michael
Penguin Books, 1964
Buku Teks
Bolton, Geoffrey Curgenven
Melbourne University Press, 1958
Buku Teks