Mixing plant species in cropping systems: concepts, tools and models. A review E. Malézieux, Y. Crozat, C. Dupraz, M. Laurans, D. Makowski, H. Ozier-Lafontaine, B. Rapidel, S. de Tourdonnet and M. Valantin-MorisonAgron. Sustain. Dev., 29 1 (2009) 43-62DOI: https://doi.org/10.1051/agro:2007057