@misc{Wilmarth_Mary_Grace_(1866-1949)_Bulletin,
 author={Wilmarth, Mary Grace (1866-1949)},
 howpublished={online},
 publisher={Government Printing Office.},
 language={eng},
 type={czasopismo},
 title={Bulletin 769. The geologic time classification of the United States Geological Survey compared with other classifications accompanied by the original definitions of era, period and epoch terms},
 keywords={geologia, mineralogia, klasyfikacja, czasopisma},
}