Conkling, Edgar C., author
McGraw-Hill, 1976
Buku Teks
Kotler, Philip, author
Maxwell Macmillan International, 1993
Buku Teks
Ella Marlena, author
2017
UI - Skripsi (Membership)
Naerssen, Anton van
Institute of Southeast Asian Studies, 1980
Buku Teks
Universitas Indonesia, 2012
UI - Skripsi (Open)