The trefoils : adaptation and culture /
[by Paul R. Henson and H.A. Schoth].
- Washington, D.C. : Agricultural Research Service, U.S. Dept. of Agriculture, 1962.
- 16 p. : ill. ; 26cm.
- Agriculture handbook / United States Department of Agriculture ; no. 223 .
- Agriculture handbook (United States. Department of Agriculture) ; no. 223. .