Borland International, 1988
Buku Referensi
editors, Richard C. Johnson, Henry Jasik
McGraw-Hill, 1987
Buku Referensi
Katz, William A., 1924-, author
Holt, Rinehart and Winston, 1979
Buku Teks
Ronan, Jana Smith, author
Libraries Unlimited, 2003
Buku Teks
Peters, Pam, author
Cambridge University Press, 1995
Buku Referensi