Mingst, Karen A.
Norton & Company, 2014
Buku Teks
edited by James N. Rosenau
Free Press, 1961
Buku Teks
Kaufman, Joyce P
Littlefield Publishers, 2013
Buku Teks
Buzan, Barry
The Harvester Press Ltd, 1983
Buku Teks
Lanyi, George A.
Random House , 1966
Buku Teks