1. The enigma of soil nitrogen balance sheets;Allison;Adv. Agron.,1955
2. The fate of nitrogen applied to soils;Allison;Adv. Agron.,1966
3. Nitrogen removal by biological suspended growth reactors;Barth,1971
4. Nitrification in the Scheldt estuary;Billen;Estuar. coast. mar. Sci.,1975
5. Evaluation de la contamination des eaux de surface en nutriments (N, P, K) par drainage des sols agricoles en Belgique;Becker;Revue Agric., Brux.,1984