Hradesky, John L., author
McGraw-Hill, 1995
Buku Referensi
Goetsch, David L., author
Pearson, 2016
Buku Teks
Tarigan, Rostiana, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2005
UI - Tesis (Membership)
Prentice-Hall, 1995
Buku Teks
Strategic Direction Publishers, [date of publication not identified]
Buku Referensi