Engeles, Frederick, author
Teplok press, 2000
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Sudaryono, author
Jurnal Pendidikan dan Kebudayaan, 2011
Artikel Jurnal
edited by Paul W. Holland and Donald B. Rubin
Academic Press, 1982
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Sukron Kamil, author
Rajawali, 2009
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edited by Bryan S. Turner
Pustaka Pelajar, 2009
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