@book{33408,
	author = {Shekhar, Shashi. and Xiong, Hui. and SpringerLink (Online service)},
	title = {Encyclopedia of GIS},
	publisher = {Springer US :},
	year = {2008.},
	address = {Boston, MA :},
	url = {http://dx.doi.org/10.1007/978-0-387-35973-1}
}