@book{6201,
	author = {Environmental Systems Research Institute (Redlands, Calif.)},
	title = {Understanding GIS:he ARC/INFO method : self-study workbook : version 7.2 for UNIX and Windows NT.  /},
	publisher = {Environmental Systems Research Institute,},
	year = {1997.},
	address = {Redlands, Calif :},
	edition = {4th ed.},
	note = {Includes index glossary and appendix.},
	url = {http://www.loc.gov/catdir/enhancements/fy0915/99462686-b.html}
}