APA

State University. Extension Service, O., State University. Cooperative Extension, W., of Idaho. Cooperative Extension System, U., William, R., Brown, K., & States. Dept. of Agriculture, U. (1987). Managing weeds and vegetation in Christmas trees. : [Corvallis, Or.] : Oregon State University Extension Service ; [Pullman, Wash.] : Washington State University Cooperative Extension ; [Moscow, Idaho] : University of Idaho Cooperative Extension System ; [Washington, D.C.] : U.S. Dept. of Agriculture.