Bunyard, R.S.
London McGraw-Hill c. 1979,
Buku Teks
Bunyard, R.S.
Macdonald & Evans Ltd., 1979
Buku Teks
Parkinson, Cyril Northcote, 1909-1993, author
Federal Publications, [Date of publication not identified]
Buku Teks
Bergeron, Leandre, author
NC Press, 1975
Buku Teks
Pickett, K.H. Spencer, author
John Wiley Sons, 2005
Buku Teks