edited by Hans Gunter
Macmillan, 1973
Buku Teks
Nainggolan, Hotman Saut, author
Fakultas Eknonomi dan Bisnis Universitas Indonesia, 2009
UI - Tesis (Open)
Chang, Leslie T., author
Spiegel & Grau, 2008
Buku Teks
Diebold, John
D> Van Nostrand Company, Inc, 1952
Buku Teks
Hopp, Wallace J., author
McGraw-Hill, 2000
Buku Teks