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Buku Teks
Dygert, James H.
Prentice-Hall, 1970
Buku Teks
Roswita Oktavianti, author
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Artikel Jurnal
Izard, Halph S., author
Hunt Publishing Company, 1977
Buku Teks
Rucker, Bryce W., author
The Iowa State Univ. Press, 1964
Buku Teks