Mitchell, David A., author
Sceptre , 2003
Buku Teks
Rand McNally, editor
Time-Life Books, 1968
Buku Referensi
Williams, Lippincott, author
Erlangga, 2010
Buku Teks
editor, Ch. Wittekind, H. Asamura, L.H. Sobin
Wiley Blackwell, 2014
Buku Referensi
edited by Jay S. Skyler
Springer, 2012
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