2002 · N. Kuptsov, J. L. Christiansen, et al. · Organic Eprints (International Centre for Research in Organic Food Systems, and Research Institute of Organic Agriculture) · 5
2002 · Bjarne Joernsgaard, J. L. Christiansen, et al. · Organic Eprints (International Centre for Research in Organic Food Systems, and Research Institute of Organic Agriculture) · 4