1. Agricultural census data (Landbouwcijfers),1995
2. The Danish Revolution, 1500–1800; An Ecohistorical Interpretation;Kjaergaard,1994
3. Agricultural Development and Nitrogen Supply from an Historical Point of View;Kjaergaard;Biological Agriculture & Horticulture,1995
4. Distribution of excreted nitrogen by grazing cattle and its effects on sward quality, herbage production and utilization;Lantinga,1987
5. Optimization of grassland production and herbage feed quality in an ecological context;Lantinga,1996