Cetron, Marvin J.
Encounters with the future : a forecast of life into the 21st century / Marvin Centron and Thomas O'Toole
McGraw-Hill, 1982
 Buku Teks
Vesterman, William
Readings for the 21st century / William Vesterman and Josh Ozersky
[publisher not identified], [date of publication not identified]
 Buku Teks
Cities in the 21st century / edited by Gary Gappert and Richard V. Knight
Sage Publications, 1982
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Hammond, Allen L.
Which world ? scenarios for the 21st Century : global destinies, regional choices
Earthscan Publications, 1998
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Gardiner, Gareth S.
21st century manager: meeting the challenges opportunities of the new corporate age
Peterso's, 1996
 Buku Teks