Riley, Jonathan
Routledge, 1998
Buku Teks
Joad, C.E.M., author
Clarendon Press, 1959
Buku Teks
Grimes, Alan P., author
Oxford University Press , 1959
Buku Teks
Ebenstein, William, author
Holt, Rinehart and Winston, 1962
Buku Teks
Roelofs, H. Mark
The Dorsey press, 1968
Buku Teks