@misc{Marshall_Robert_Bradford_(1867-1949)_Bulletin,
 author={Marshall, Robert Bradford (1867-1949)},
 howpublished={online},
 publisher={Government Printing Office.},
 language={eng},
 title={Bulletin 638. Spirit leveling in New Mexico 1902 to 1915, inclusive},
 type={journal},
 keywords={United States of America, geology, mineralogy, journals},
}