Kerr, James
Cambridge University Press, 1989
Buku Teks
Noble, James.
Oliver & Boyd,, 1982.
Buku Teks
Carr, Houston H., author
McGraw-Hill, 2003
Buku Teks
Association for Higher Education , 1963
Buku Teks
White, James J., author
West Group, 1995
Buku Teks