Clarendon Press , 1987
Buku Teks
The Free Press, 1950
Buku Teks
Wolff, J. S.
Arnold, [date of publication not identified]
Buku Teks
Wolff, Robert Lee, author
Garland Publishing, 1981
Buku Referensi
Wolff, Robert Lee, author
Garland Publishing, 1985
Buku Referensi