Warto
Universitas Indonesia, 1993
UI - Tesis Membership
edited by Jurgen Georg Backhaus
Springer, 2012
eBooks
editedby R.N. Baldwin
Oceana Publications, 1953
Buku Teks SO
Thomann, Lars
VS Verlag, 2011
eBooks
Nathalia Christine
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2018
UI - Skripsi Membership