http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Spatial variation in total element concentration in soil within the northern Great Plains coal region
35 pages in various pagings : illustrations, maps ; 29 cm.
by R.C. Severson and R. R. Tidball and Regional soil chemistry in the Bighorn and Wind River Basins, Wyoming and Montana / by R. C. Severson.
"Geochemical survey of the the western energy regions."
Geological Survey professional paper ; 1134 A,B