?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Sivakumar%2C+M+V+K&rft.aufirst=M+V+K&rft.aulast=Sivakumar&rft.date=1992&rft.title=Relation+between+climate+and+soil+productivity+in+the+tropics&rft.genre=proceeding