Stone, Richard, author
Blackstone Press, 1996
Buku Referensi
Macintryre, Ewan, author
Blackstone Press, 1998
Buku Referensi
Tracey, Richard R.S., author
Butterworth, 1975
Buku Teks
Countryman, Vern, author
Little, Brown, 1971
Buku Teks
Gunther, Gerald, author
Foundation Press, 1970
Buku Teks