Description
Item Description:Title from PDF title screen (viewed on Dec. 28, 2006).
Physical Description:iv, 28 pages : digital, PDF file.
Format:Mode of access: Internet from the USGS web site. Address as of 10/11/07: http://pubs.usgs.gov/of/2006/1374/pdf/ofr20061374.pdf; current access via PURL.
Bibliography:Includes bibliographical references (page 10).