Shackelford, James F., author
Macmillan Press, 1990
Buku Teks
Shackelford, James F., author
Prentice-Hall, 1996
Buku Teks
Shackelford, James F., author
Prentice Hall International, 1996
Buku Teks
Parker, Earl R.
McGraw-Hill, 1967
Buku Teks
Derucher, Kenneth N.
Prentice-Hall, 1981
Buku Teks