By National Geographic Society
By United Nations Development Programme, United Nations Environment Programme, World Resources Institute
By Cleare, John
By King, Ross
By Cleave, Andrew
By Skinner, Malcolm, Redfern, David, Farmer, Geoff
By Ellen Gunter, Ted Carter
By Hall, Lincoln
By George McDonald
By Hunter, Beatrice Trum
By Rick Steves
By Derek Gow
By Hyatt, Neil C., Pickett, David A., Rebak, Raul B.
By Primack, Richard B., Sher, Anna
By Islam, Shafiqul
By Catherine Kleier
By Linda Chalker-Scott
By Farfor, Susannah, Kirby, Jill, Dunford, George
By Helen Gillman, etc.
By Fletcher, JoAnn, Humphreys, Andrew, Jenkins, Siona, Sattin, Anthony
By Garwood, Duncan
By Johnstone, Sarah, Masters, Tom
By NO AUTHOR
By Seidensticker John, Lumpkin Susan
By Milner Angela
By Webb, Sally, Hughes, Martin
By Bao, Sandra, Beech, Charlotte, Dydynski, Krzysztof
By Hughes, Martin