Kaplan, David, author
Pustaka Pelajar, 2012
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UI - Tesis (Membership)
Carr, Stuart C., author
John Wiley and Sons Australasia , 2003
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Brym, Robert J., author
Wadsworth and Cengage Learning, 2013
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Fiske, Susan T., author
Sage , 2013
Buku Teks