Chicago

Fitzsimmons, Jim P., L. C Burrill, Oregon State University. Extension Service, Washington State University. Cooperative Extension, University of Idaho. Cooperative Extension System, and United States. Dept. of Agriculture. 1993. St. Johnswort, Hypericum Perforatum L. : [Corvallis, Or.] : Oregon State University Extension Service ; [Olympia, Wash.] : Washington State University Cooperative Extension ; [Moscow, Idaho] : University of Idaho Cooperative Extension System ; [Washington, D.C.] : U.S. Dept. of Agriculture.