@misc{Hopkins_Oliver_B._Bulletin,
 author={Hopkins, Oliver B.},
 copyright={Biblioteka Politechniki Gdańskiej},
 howpublished={online},
 publisher={Government Printing Office.},
 language={eng},
 type={czasopismo},
 title={Bulletin 641-D. Structure of the Vicksburg-Jackson Area, Mississippi},
 keywords={geologia, mineralogia, czasopisma, Stany Zjednoczone},
}