?url_ver=Z39.88-2004&rft_id=10.1016%2FS1571-0661(05)80249-X&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=De+Nicola%2C+Rocco&rft.aufirst=Rocco&rft.aulast=De+Nicola&rft.issn=1571-0661&rft.title=Electronic+Notes+in+Theoretical+Computer+Science&rft.date=1998&rft.pages=46-64&rft.atitle=Tree+morphisms+and+bisimulations&rft.volume=18&rft.genre=article