Parkhurst, Wiliam
Harper Business, 2000
Buku Teks
Alya, author
2007
UI - Tesis (Membership)
Ramacitti, david F.
Amacom, 1991
Buku Teks
Awing Priscilla Purnomo, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2010
UI - Skripsi (Open)
Baus, Herbert M
Harper & Brothers, 1948
Buku Teks