Libraries Unlimited, 1988
Buku Referensi
Kokusai Bunka Shinkokai, author
Kokusai Bunka Shinkokai, 1969
Buku Teks
Wright, John Kirtland, author
Columbia University Press, 1947
Buku Teks
editor in chief, Mortimer J. Adler
Encyclopaedia Britannica, 1996
Buku Referensi
Sullivan, Michael, author
[American Management Association, ], 2009
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