Distributed to depository libraries in microfiche.
Also available via Internet from the USGS web site. Address as of 7/27/02: http://vulcan.wr.usgs.gov/Projects/Mastin/Publications/OFR93-445/; current access is available via PURL.
Microfiche. [Denver, Colo. : U.S. Geological Survey, 1995] 1 microfiche.