Brown, Jeannette A
Brooks.Cole, 1983
Buku Teks
Stewart, William, author
How to Books, 1999
Buku Teks
Stone, Gerald L
Brooks/Cole, 1985
Buku Teks
Janita Widjaja, author
1988
UI - Skripsi (Membership)
editor, Don C. Locke, Jane E. Myers, Edwin L. Herr
Sage, 2001
Buku Referensi