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Buku Teks
Organski, A.F.K., author
Alfred A. knopt, 1967
Buku Teks
Little, Brown & Co., 1982
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Daulay, Saleh Partaonan, author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2002
UI - Tesis Membership
Banfield, Edward C., author
Random House, 1967
Buku Teks