?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.aufirst=David&rft.aulast=Walker&rft.au=Walker%2C+David&rft.title=From+Metasearch+to+Meta-services%3A+Rethinking+the+Goals+and+Benefits+of+Metasearching+Using+the+MetaLib+X-server+&rft.date=31+July+2008&rft.genre=proceeding