1. Measuring sustainability;Barnett;Environ. Ecol. Stat.,1994
2. Bichel Committee, 1999. Rapport fra den Tværfaglige økologigruppe (Report from the interdiciplinary group on organic farming). Report from The Danish Environmental Protection Agency, Copenhagen, ISBN 87-7909-292-6, 98 pp.
3. Bleken, M.A., Bakken, L.R., 1997. The anthropogenic nitrogen cycle in Norway. In: Romstad, E., Simonsen, J., Vatn, A. (Eds.), Controlling Mineral Emissions in European Agriculture, Vol. 2. CAB International, Wallingford, pp. 27–40.
4. Bowers, W., 1992. Agricultural field equipment. In: Fluck, R.C. (Ed.), Energy in Farm Production, Vol. 10. Elsevier, Amsterdam, ISBN 0-444-88681-8, pp. 117–129.
5. Soil map of Denmark according to the revised FAO legend 1990;Breuning-Madsen;Danish J. Geogr.,1996