Hart, Chris, author
Sage, 2003
Buku Teks
Saunders, Joy, author
Pearson Education, 1994
Buku Teks
Hildebrandt, Darlene Myers, author
Computing Information Directoy, 1995
Buku Referensi
Katz, Saul M., author
University of Pittsburgh, 1965
Buku Teks
Eble, Kenneth E., author
Jossey-Bass, 1978
Buku Referensi