Ofori, George
Singapore University Press, 1990
Buku Teks
Myers, Danny, author
Taylor and Francis, 2009
Buku Teks
Shutt, R.C.
Longman Scientific and Technical, 1995
Buku Teks
Singhs KS., Harban , author
LexisNexis, 2011
Buku Teks
Clough, Richard Hudson, author
John Wiley & Sons, Inc, 1994
Buku Teks