Roskin, Michael G., 1939-, author
Pearson Education, 2015
Buku Teks
Palmer, Monte, author
Thomson, 2006
Buku Teks
edited by George E. Delury
Facts on File, 1994
Buku Referensi
Christian Soe
McGraw-Hill, 2004
Buku Teks
Chilcote, Ronald H., author
Routledge, 2000
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