By Rudiger Wurzel, James Connelly (University of Hull, UK)
By Jennifer Elliott
By Jan J. Tuma
By Franklin Fisher, Annette Huber-Lee
By Julian Caldecott
By Jonathan Wills
By Alison Benjamin, Brian McCallum
By W. Carl Gottschall (Consultant, Littleton, Colorado), Douglas B. Walters (President, KCP, Inc., Raleigh, North Carolina)
By Bent Flyvbjerg (Aalborg University, Denmark), Nils Bruzelius (Stockholms Universitet), Werner Rothengatter (Universitat Fridericiana Karlsruhe, Germany)
By Brian Clegg
By Christian Parenti
By Patrick Galbraith
By Robin Mearns, Melissa Leach
By United Nations Environment Programme
By Castells, Manuel
By Martin Kellman, Rosanne Tackaberry
By Temple Grandin
By Mansoor M. Amiji
By Dismukes, R. Key, Berman, Benjamin A., Loukopoulos, Loukia
By Ashton
By Crompton, Tr
By A. L. Wilson, D. T. E. Hunt
By Goudie, Andrew S.
By Smith, G. N.
By Webber, N.B.
By Raw, Michael, Atkins, Peter
By Nicholas P Cheremisinoff, Consulting Engineer (Director of Clean Technologies and Pollution Prevention Projects at Princeton Energy Resources International, LLC, Rockville, MD, USA)
By A. Bolisher, etc.
By J.E. Cooper