5Brundtland G H,Khalid M.Report of World Commission on Environment and Development[]..1987
6Oldeman L R.The global extent of soil degradation[].Soil resilience and sustainable land use.1994
7Young A.Land resources:now and for the future[]..1998
8World Bank.World development report:infrastructure for development[]..1994
9Oldeman L,van Engelen V,Pulles J.The extent of hymaninduced soil degradation,Annex5[].World Map of the Status of Human Induced Soil DegrdationAn Explanatory Note.1990
10Land and Water Development Division,Food and Agriculture Organization of the United Nations Rome.Land Resource Potential and Constraints atRegional and Country Levels[].World Soil Resources Reports.2000
