1. Anonymous 1997 Vedledning og skemaer, mark- og gødningsplan, gødningsregnskab, grønne marker 1997/98 (Guidelines and schemes, field- and fertilization-plans, fertilization accounts, green fields 1997/98)
2. Anonymous 2004 Statistik over økologiske jordbrugsbedrifter 2003 (Organic farming statistics, 2003)
3. Berntsen J Petersen BM Kristensen IS Olesen JE 2004 Nitratudvaskning fra økologiske og konventionelle planteavlsbedrifter - simuleringer med FASSET bedriftsmodellen (Nitrate leaching from organic and conventionel arable crop rotations - simulations with the FASSET farm model)
4. Best EK 1975 An automated method for determining nitrate-nitrogen in soil extracts
5. Nitrate leaching after cut grass/clover leys as affected by time of ploughing;Djurhuus;Soil Use and Management,1997