University of Arkansas (System). Cooperative Extension Service & United States. Department of Agriculture. (1973). Circular. Cooperative Extension Service, University of Arkansas, Division of Agriculture and U.S. Dept. of Agriculture, cooperating.
Παραπομπή σε μορφή Chicago (17η εκδ.)University of Arkansas (System). Cooperative Extension Service και United States. Department of Agriculture. Circular. [Little Rock, Ark.]: Cooperative Extension Service, University of Arkansas, Division of Agriculture and U.S. Dept. of Agriculture, cooperating, 1973.
Παραπομπή σε μορφή MLA (8th εκδ.)University of Arkansas (System). Cooperative Extension Service και United States. Department of Agriculture. Circular. Cooperative Extension Service, University of Arkansas, Division of Agriculture and U.S. Dept. of Agriculture, cooperating, 1973.