Mode of access: Internet from the USGS web site. Address as of 8/5/04: http://water.usgs.gov/wid/html/SG.html#HDR8 ; current access is available via PURL.
General Note:
Title from title screen (viewed Aug. 5, 2004). Authors: Kenneth L. Wahl, Wilbert O. Thomas, Jr., and Robert M. Hirsch.