p40sAr/p39sAr age-spectrum and laser fusion data for volcanic rocks in west central Colorado [electronic resource] / by Michael J. Kunk, Jeffrey A. Winick, and Josette O. Stanley.
Imprint
[Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2001.
Mode of access: Internet from the USGS web site. Address as of 3/5/03: http://pubs.usgs.gov/of/2001/ofr-01-472/OFR-01-472-508.pdf; current access is available via PURL.