1. Abrol YP, Sangwan S and Tiwari MK (eds) (2002) Land Use-Historical Perspective–Focus on Indo-Gangetic Plains. Allied Publishers, New Delhi
2. Alcamo J, Krol M and Posch M (1995) An integrated analysis of sulphur emission acid deposition and climate change. Water Air Soil Pollu
85: 1539–1550
3. Ceccotti S and Messick D (1994) Plant nutrient sulphur: A global review of crop requirements, supply, and environmental impact on nutrient balance. Norwegian JAgric Sci
15: 7–25
4. FAO (1996) World Food Summit. Technical Background Documents. 23: 12–15.
5. FAO, Rome FAO (2000) Agriculture: Towards 2015/2030. Technical Interim Report, FAO Rome