?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.aufirst=S+H&rft.au=Chien%2C+S+H&rft.aulast=Chien&rft.atitle=Agronomic+evaluation+of+two+unacidulated+and+partially+acidulated+phosphate+rocks+indigenous+to+Niger&rft.title=Soil+Science+Society+of+America+Journal&rft.issn=0361-5995&rft.date=1990&rft.volume=54&rft.pages=1772-1777&rft.issue=6&rft.genre=article