@book{138003,
	author = {Evenson, Robert E. and ebrary, Inc.},
	title = {Crop variety improvement and its effect on productivity},
	publisher = {CABI Pub.,},
	year = {c2003.},
	address = {Wallingford, Oxon, UK ;},
	url = {http://site.ebrary.com/lib/rucke/Doc?id=10173518}
}