@book{11815,
	author = {Henson, P. R. and Schoth, H. A.},
	title = {The trefoils :},
	publisher = {Agricultural Research Service, U.S. Dept. of Agriculture,},
	year = {1962.},
	series = {Agriculture handbook / United States Department of Agriculture ;},
	address = {Washington, D.C. :}
}