Description
Item Description:Title from Web page (viewed on Sept. 28, 2007).
Electronic resource.
Physical Description:viii, 89 pages : digital, PDF file.
Format:System requirements: PDF reader.
Mode of access: World Wide Web from the USGS web site. Address as of 7/14/08: http://pubs.usgs.gov/circ/2007/1302/ ; current access available via PURL.
Bibliography:Includes bibliographical references (pages 82-89).
ISBN:141131252X (alk. paper)
9781411312524 (alk. paper)