iii, 30 pages : color illustrations, color map ; 28 cm
OCLC
ocm54532694
Includes bibliographical references (pages 24-26).
Also available via Internet at the USGS web site. Address as of 03/05/04: http://water.usgs.gov/pubs/wri/wri034145/pdf/wri034145.pdf; current access available via PURL.