Levinson, Nan
[American Management Association;, ], 2000
eBooks
Ries, Al
McGraw-Hill, 1986
Buku Teks
Griya Ratri Putri
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2012
UI - Skripsi (Open)
Time Warner, 2005
Buku Teks
Richman, Larry
American Management Association, 2006
eBooks