Gilmore, Grant
The Foundation Press, Inc., 1975
Buku Teks
Fernandes, Rui M.
Carswell, 1995
Buku Teks
Ehrenzweig, Albert A.
Leiden A.W. Sijthoff 1973,
Buku Teks
Maraist, Frank L., author
West Publishing, 1996
Buku Teks
general editors, Clive Parry, John P. Grant, Anthony Parry, Arthur D. Watts
Oceana Publications, 1988
Buku Referensi