?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=R+W&rft.au=Willey%2C+R+W&rft.aulast=Willey&rft.atitle=A+Competitive+ratio+for+quantifying+competition+between+intercrops&rft.title=Experimental+Agriculture&rft.issn=0014-4797&rft.date=1980&rft.volume=16&rft.pages=117-125&rft.issue=2&rft.genre=article