Iowa State College. Agricultural Experiment Station & Iowa State College. Agricultural Extension Station. (1939). Bulletin P. Agricultural Experiment Station--Agricultural Extension Service, Iowa State College.
Lua i Stíl Chicago (17ú heag.)Iowa State College. Agricultural Experiment Station agus Iowa State College. Agricultural Extension Station. Bulletin P. Ames, Iowa: Agricultural Experiment Station--Agricultural Extension Service, Iowa State College, 1939.
Lua MLA (8ú heag.)Iowa State College. Agricultural Experiment Station agus Iowa State College. Agricultural Extension Station. Bulletin P. Agricultural Experiment Station--Agricultural Extension Service, Iowa State College, 1939.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.