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Majalah, Jurnal, Buletin
Queensland : The University of Queensland Press, 1985
Majalah, Jurnal, Buletin
Aristotle
Modern Library, 1943
Buku Teks
Faculty of international studies, Prince of Songkala university,
Majalah, Jurnal, Buletin
Soltau, Roger H.
Longmans, Green , 1951
Buku Teks