Description
Item Description:Title from PDF title screen (viewed on July 3, 2007).
Electronic resource.
Physical Description:iv, 10 pages : digital, PDF file.
Format:Mode of access: Internet from the USGS web site. Address as of 11/7/07: http://pubs.usgs.gov/of/2007/1083/pdf/OFR2007-1083.pdf ; current access via PURL.
Bibliography:Includes bibliographical references (page 10).