Ahmad Taufik
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2002
UI - Tesis Membership
Hutabarat, Hermin
Gunung Mulia, 1989
Buku Teks
Post, Peggy
HarperCollins Publishers, 2004
Buku Teks
Beyfus, Drusilla
Reed International Books, [date of publication not identified]
Buku Teks
Mayeroff, Milton
Gramedia Pustaka Utama, 1993
Buku Teks