editorial direction by Martin Nicholas Kunz ; English translation, Robert Kaplan
Daab, 2004
Buku Teks SO
Sinaga, Elmi Rina Marsinta
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2010
UI - Skripsi Open
Mano, M. Morris, 1927-
Prentice Hall International , 1991
Buku Teks
Lefteri, Chris
Laurence King Publishing, 2014
Buku Teks
Eggert, Rudolph J.
Pearson/Prentice Hall, 2005
Buku Teks