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Wadsworth, 2010
Buku Teks
Stiebing, William H.
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Buku Teks
Mongait, Alexander, author
Foreign Languages Publishing House, 1959
Buku Teks
Sharer, Robert J., author
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Buku Teks
Deetz, James.
Natural History Press for the American Museum of Natural Histor, 1967
Buku Teks