Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds - Lotz, L.A.P.; Christensen, S.; Cloutier, D.; Fernandez Quintanilla, C.; Legere, A.; Lemieux, A.; Lutman, P.J.W.; Pardo Iglesias, A.; Salonen, Jukka; Sattin, M.; Stigliani, L.; Tei, F. (gb, 1996)