Washington State University. Cooperative Extension & United States. Department of Agriculture. (2001). Perennials for the Inland Northwest (Rev. Sept. 2001.). Washington State University Cooperative Extension ; U.S. Dept. of Agriculture.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Washington State University. Cooperative Extension và United States. Department of Agriculture. Perennials for the Inland Northwest. Rev. Sept. 2001. [Pullman, Wash.] : [Washington, D.C.]: Washington State University Cooperative Extension ; U.S. Dept. of Agriculture, 2001.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Washington State University. Cooperative Extension và United States. Department of Agriculture. Perennials for the Inland Northwest. Rev. Sept. 2001. Washington State University Cooperative Extension ; U.S. Dept. of Agriculture, 2001.