1. The world fertilizer situation;Aller;World Dew,1977
2. 'Technology in the 1990s: Agriculture and Food.”;Blaxter,1985
3. “Soil Erosion: Quiet Crisis in the World Economy,”;Brown,1984
4. “State of the World 1984.”;Brown,1984
5. “State of the World 1985.”;Brown,1985