Feigenbaum, Edward A.
The fifth generation artificial intelligence and Japan's computer challenge to the world
Michael Joseph, 1984
 Buku Teks
Bessant, John
Managing advanced manufacturing technology: the challenge of the fifth wave
Blackwell, 1991
 Buku Teks SO
Handelman, Howard
The challenge of third world development
Pearson/Prentice Hall, 2006
 Buku Teks
The world economy: a global challenge
United Nations Departemen of Public Information, 1990
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Wortman, Sterling
To feed this world : the challenge and the strategy
Johns Hopkins University Press, 1979
 Buku Teks SO