?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=+Het%C3%A9nyi+Magdolna&rft.aulast=Het%C3%A9nyi&rft.aufirst=Magdolna&rft.volume=22&rft.issn=0365-8066&rft.title=Acta+mineralogica-petrographica&rft.pages=231-239&rft.atitle=Contributions+to+the+isolation+of+the+kerogen+in+Hungarian+oil+shales&rft.date=1976&rft.issue=2&rft.genre=article