The Unesco Press, 1974
Buku Teks
Amoo, Sam G.
United Nations Development Programme, 1997
Buku Teks
Routledge, 1997
Buku Teks
edited by Nathan Glazer and Daniel P. Moynihan, with the assistance of Corinne Saposs Schelling
Harvard University Press, 1975
Buku Teks
Cambridge University Press, 2006
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