Pepper, Stephen C.
World hypotheses: a study in evidence
University of California Press, 1966
 Buku Teks SO
The World of Ideas: essays for study
edited by Michael W. Alssid, William Kenney
Holt, Rinehart and Winston, 1964
 Buku Teks
World insolvency systems : a comparative study
Otto Eduardo Fonseca Lobo
Carswell , 2009
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Luard, Evan
Nationality and wealth a study in world government
Oxford University Press, 1964
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Bull, Hedley
The anarchical society: a study of order in world politics
Macmillan, 1995
 Buku Teks SO