?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Bj%C3%83%C2%B6rkman%2C+Maria&rft.aulast=Bj%C3%83%C2%B6rkman&rft.aufirst=Maria&rft.date=2006&rft.title=Intercropping+systems+-+Optimising+crop+protection+and+reducing+competition&rft.genre=proceeding