TY  - RPRT
TI  - History and evaluation of national-scale geochemical data sets for the United States
AU  - David B. Smith
AU  - Steven M. Smith
AU  - John D. Horton
PY  - 2013
DO  - 10.1016/j.gsf.2012.07.002
UR  - https://pubs.usgs.gov/publication/70044948
ID  - 70044948
ER  -