Anmerkungen:
"May 2009
Includes bibliographical references (p. [6])
Mode of access: Internet from the USGS web site. Address as of 5/27/09: http://pubs.usgs.gov/fs/2009/3032/pdf/FS2009-3032.pdf; current access available via PURL
Mode of access: Internet from the USGS web site. Address as of 5/27/09: http://pubs.usgs.gov/fs/2009/3032/pdf/FS2009-3032.pdf; current access available via PURL