TY  - BOOK
AU  - Helgesen,John O.
AU  - Leonard,Robert B.
AU  - Wolf,Ronald J.
ED  - United States.
ED  - United States.
TI  - Hydrology of the Great Plains aquifer system in Nebraska, Colorado, Kansas, and adjacent areas
PY  - 1993///
CY  - Washington
PB  - U.S. Government Printing Office
ER  -