editor, John G. Webster
John Wiley & Sons, 1998
Buku Teks
Turner, J.D., author
Macmillan, 1988
Buku Teks
Leslie Cromwell [and others]
Prentice-Hall, 1976
Buku Teks
Tompkins, Willis J., author
Prentice-Hall, 1981
Buku Teks
Srivastava, A.C., author
Vani Educational Books, [Date of publication not identified]
Buku Teks