Barke, Michael
Longman Scientific & Technical, 1991
Buku Teks SO
Keohane, Robert Owen, 1941-, author
Longman, 2012
Buku Teks
Daillant, Georges
International Universities Bureau of the International Association of Universities, 1990
Buku Referensi
edited by Donald Eugene Smith
Free Press, 1971
Buku Teks
Beneit, Emile ed.
N.Y. Columbia University Press , 1967
Buku Teks