@book{49049,
	author = {Uphoff, Norman Thomas},
	title = {Biological approaches to sustainable soil systems /},
	publisher = {CRC/Taylor & Francis,},
	year = {2006},
	address = {Boca Raton :},
	url = {http://www.loc.gov/catdir/enhancements/fy0661/2005034628-d.html}
}