TY  - BOOK
AU  - Crock J.G.
AU  - Severson,R.C.
TI  - Four Reference Soil And Rock Samples for Measuring Element Availability in the Western Energy Regions :
T2  - Geological Survey Circular
U1  - 557.30973 
PY  - 1980///
CY  - Washington, D.C.
PB  - United States Geological Survey
KW  - Geology
KW  - Washington Metropolitan Area
KW  - United States
KW  - Geological surveys
KW  - History
ER  -