?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Rasmussen%2C+Jesper&rft.aulast=Rasmussen&rft.aufirst=Jesper&rft.date=2004&rft.title=Are+we+making+progress+in+mechanical+weed+control+research%3F+&rft.genre=proceeding