?url_ver=Z39.88-2004&rft_id=10.1080%2F13504509509469889&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Yousif%2C+H.M.&rft.aulast=Yousif&rft.aufirst=H.M.&rft.issue=1&rft.volume=2&rft.date=1995&rft.issn=1745-2627&rft.atitle=Population%2C+biomass+and+the+environment+in+central+Sudan&rft.title=International+Journal+of+Sustainable+Development+and+World+Ecology&rft.pages=54-69&rft.genre=article