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Thomson wadsworth, 2004
Buku Teks
Ehrenhalt, Alan, author
Yayasan Obor, 2006
Buku Teks
Thayer, Frank
The Foundation Press,Inc., 1962
Buku Teks
Nelson, Harold L.
The Foundation Press,Inc., 1969
Buku Teks
Nelson, Harold L.
The Foundation Press,Inc., 1978
Buku Teks