Artikel Jurnal
Sirait, Ramli, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2004
UI - Tesis (Membership)
Walters, Roger L., author
McGraw-Hill, 1994
Buku Teks
Orlik, Peter B., author
Allyn & Bacon, 1994
Buku Teks
Dancyger, Ken, author
Focal Press, 1991
Buku Teks