Baltimore, Md. : U.S. Dept. of the Interior, U.S. Geological Survey ; Denver, CO : U.S. Geological Survey, Branch of Information Services [distributor], 2002
iv, 39 pages : color illustrations, color maps ; 28 cm
OCLC
ocn244827260, ocm50597957
Includes bibliographical references (pages 13-15).
Also available via Internet from the USGS web site. Address as of 9/3/08: http://pubs.usgs.gov/wri/wri01-4216/wrir-01-4216.pdf ; current access available via PURL.