Fordham, Paul
Penguin Books, 1972
Buku Teks
Griffiths, Ieuan Ll., author
Routledge, 1994
Buku Teks
Davidson, Basil, author
Time-Life International, 1967
Buku Teks
July, Robert W
Charles Scribner's, 1970
Buku Teks
Kennedy, Scott
Charles Scribner's , 1973
Buku Teks