World Map of the Status of Human-Induced Soil Degradation. An Explanatory Note. (Global Assessment of Soil Degradation GLASOD)
Oldeman, L.R.; Hakkeling, R.T.A.; Sombroek, W.G.
International Soil Reference and Information Centre (ISRIC), United Nations Environment Programme (UNEP), in cooperation with Winand Staring Centre, International Soil Science Society, Food and Agricultur Organization of the United Nations (FAO), International Institute for Aerospace Survey and Earth Science (ITC).