State University. Cooperative Extension Service, Oregon, University of Idaho. Agricultural Extension Service, Washington State University. Cooperative Extension Service, and Pacific Northwest Cooperative Extension. 1974. Longspine Sandbur. : [Corvallis, Or.?] : Cooperative Extension Services of Oregon State University ; [Pullman, Wash.] : Washington State University Cooperative Extension Service ; [Moscow, Idaho] : University of Idaho Agricultural Extension Service ; [Washington, D.C.] : U.S. Dept. of Agriculture.