1. Total nitrogen;Bremner,1965
2. Nitrogen availability indexes;Bremner,1965
3. Steam distillation methods for determination of ammonium, nitrate and nitrite;Bremner;Anal. Chem. Acta,1965
4. The role of shrubs in nutrient cycling;Charley,1972
5. Changes in soil nutrient status resulting from overgrazing and their consequences in plant communities of semi-arid areas;Charley,1968