Denny J.A.
Pustaka Sinar Harapan, 2006
Buku Teks SO
Buku Teks SO
International IDEA
International IDEA, 2000
Buku Teks SO
Norbert Eschborn; Joyce Holmes Richardson; Henriette Litta
Konkrad-Adenauer-Stiftung, 2005
Buku Teks SO
Marco Bunte
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Buku Teks SO