Andrew I. Cohen: Christopher Health Well,am
Blackwell, 2005
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Hutabarat, Nadia Carolina
Universitas Indonesia, 2015
UI - Skripsi Membership
Keeble, Richard
Routledge, 2001
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Naroll, Raoul
Sage, 1983
Buku Teks
Hausman, Carl
Harper Collins, 1992
Buku Teks