Roskin, Michael G., 1939-, author
Pearson, 2017
Buku Teks
Academy of Political Science, 2018
Majalah, Jurnal, Buletin
Bodlaender, M. L., author
Uitgeversmaatschappij Elsevier, 1950
Buku Teks
Barents, J. (Jan), author
Erlangga, 1983
Buku Teks
Field, G. Lowell, author
Buku Teks