@book{29830,
	author = {Grigg, David B.},
	title = {The agricultural systems of the world :},
	publisher = {Cambridge University Press,},
	year = {c1974.},
	address = {London ;},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/description/cam032/73082451.html}
}