?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Hauggaard-Nielsen%2C+Henrik&rft.aulast=Hauggaard-Nielsen&rft.aufirst=Henrik&rft.date=2006&rft.title=Competitive+ability+of+grain+legume-barley+intercrops+towards+volunteer+crops+and+weeds&rft.genre=proceeding