Managing organic resources in agriculture: future challenges from a scientific perspective oleh Gerard L. Velthof, Gerard L. Velthof, Twan C. A. Cals, Jordy P. van 't Hull, Jan Peter Lesschen, Malte Lessmann, Malte Lessmann, Rima J. Porre, Mart B. H. Ros, René P. J. J. Rietra, Oscar F. Schoumans, Lotte Veenemans, Dorien Westerik