By Hugh Raffles
By Macdonald, David W.
By Malcolm B. Wilkins
By Small, R. J.
By Dorling Kindersley
By E. Gene Frankland, Donald Schoonmaker
By Hermes, Neil
By Francis Robinson
By TickTock Books
By Norman Myers
By Philip Kearey (Lecturer in Applied Geophysics, University of Bristol), Frederick J. Vine (Professor of Environmental Sciences, University of East Anglia, Norwich)
By Daan Smit, Nicky Den Hartogh
By Sparks, John, Drozhov, Nikolai
By Richard Hockin, etc.
By Augustin Rodriguez-Bachiller
By Robson, Brian T.
By Ian Mercer, G. Cressey (Researcher in Mineral Sciences, The Natural History Museum, London)
By Norman Myers, Time-Life Books.
By Tony Hare
By Roberts, Jonathan
By Thandika Mkandawire, Naceur Bourenane
By Attenborough, David
By Hammond, Nicholas, Packhan, Chris
By Paul Sterry
By Barth, G.M-., Darlington, A.
By Gooders, John, Cooper, Stuart, Harris, Alan
By OECD: Organisation for Economic Co-Operation and Development