?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=+Thi+Vu+Duc&rft.aufirst=Vu+Duc&rft.aulast=Thi&rft.title=Acta+cybernetica&rft.issue=1-2&rft.date=1991&rft.pages=93-100&rft.issn=0324-721X&rft.volume=10&rft.atitle=Weak+dependecnies+%5B!dependencies%5D+in+the+relational+datamodel&rft.genre=article