Yayasan Proklamasi, [date of publication not identified]
Buku Teks SO
Stern, Robert W., 1933-
Cambridge University Press, 2003
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Vernon, Raymond
Committee for Economic Development, 1954
Buku Teks SO
Institute Studies, 1984
Buku Teks SO
edited by Andrew Blasko, Diana Januauskiene
Council for Research in Values and Philosophy, 2008
Buku Teks SO