?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.aufirst=E+C&rft.au=Mussaa%2C+E+C&rft.aulast=Mussaa&rft.date=2011&rft.title=Resource+use+efficiency+of+smallholder+crop+production+in+the+central+highlands+of+Ethiopia&rft.genre=proceeding