Title from PDF title screen (viewed on Feb. 21, 2007).
Bibliography Note:
Includes bibliographical references (pages 32-33).
Technical Details:
Mode of access: Internet from the USGS web site. Address as of 10/10/07: http://pubs.usgs.gov/of/2006/1363/pdf/OF06-1363%5F508.pdf; current access via PURL.