?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.aufirst=D&rft.au=Valbuena%2C+D&rft.aulast=Valbuena&rft.date=2011&rft.title=Trade-offs+of+crop+residue+use+in+smallholder+mixed+farming+systems+in+Sub-Saharan+Africa+and+South+Asia&rft.genre=proceeding