?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Delva%2C+Willy&rft.aulast=Delva&rft.aufirst=Willy&rft.date=1980&rft.btitle=Algemene+beginselen+van+het+recht&rft.genre=book