1. Composition of macro geographical (continental) regions, geographical sub-regions, and selected economic and other groupings
http://millenniumindicators.un.org/unsd/methods/m49/m49regin.htm
2. World reference base for soil resources 2006,2006
3. Soil Atlas of Europe,2005
4. Agriculture, Forestry and Nature, Trends and Development across Europe;Bregt,2002
5. State of the World’s Forests,2012