Description
Item Description:Title from PDF title screen (viewed Oct. 13, 2004).
Electronic resource.
Physical Description:iv, 19 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/2004/1330/pdf/ofr20041330.pdf ; current access via PURL.
Bibliography:Includes bibliographical references (page 19).