Foreword by William R. Mead
Tiger Book International, 1995
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edited by Malcolm Warner
Business Press, 2000
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Washington : Pan American Union, General Secretariet of the Organization of American States
Majalah, Jurnal, Buletin
GK-Hall, 1994
Buku Teks
Bettany, G.T., author
Bracken Books, [date of publication not identified]
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