?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adissertation&rft.au=Heckendorn%2C+Felix&rft.aulast=Heckendorn&rft.aufirst=Felix&rft.date=2007&rft.title=The+control+of+gastrointestinal+sheep+nematodes+with+tanniferous+forage+plants&rft.inst=Swiss+Federal+Institute+of+Technology+Zurich%2C+CH