Description
Item Description:Title from PDF title screen (viewed on Jan. 4, 2008).
Electronic resource.
Physical Description:iv, 30 pages : digital, PDF file.
Format:Mode of access: Internet from the USGS web site. Address as of 1/7/08: http://pubs.usgs.gov/of/2007/1430/pdf/ofr20071430.pdf ; current access via PURL.
Bibliography:Includes bibliographical references (pages 9-10).