Description
Item Description:Title from PDF title page (viewed Apr. 17, 2007).
At head of title on HTML title screen: USGS Virginia Water Science Center.
Electronic resource.
Physical Description:ix, 118 pages : digital, PDF file
Also available in print.
Format:Mode of access: Internet at the USGS web site. Address as of 7/24/08: http://pubs.usgs.gov/pp/2006/1731/PP1731.pdf ; current access is available via PURL.
Bibliography:Includes bibliographical references.