@misc{Marshall_Robert_Bradford_(1867-1949)_Bulletin,
 author={Marshall, Robert Bradford (1867-1949)},
 howpublished={online},
 publisher={Government Printing Office.},
 language={eng},
 type={journal},
 title={Bulletin 643. Spirit leveling in south Dakota},
 keywords={geology, mineralogy, journals, United States of America},
}