Iowa State College. Agricultural Experiment Station & Iowa State College. Agricultural Extension Station. (1939). Bulletin P. Agricultural Experiment Station--Agricultural Extension Service, Iowa State College.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Iowa State College. Agricultural Experiment Station و Iowa State College. Agricultural Extension Station. Bulletin P. Ames, Iowa: Agricultural Experiment Station--Agricultural Extension Service, Iowa State College, 1939.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Iowa State College. Agricultural Experiment Station و Iowa State College. Agricultural Extension Station. Bulletin P. Agricultural Experiment Station--Agricultural Extension Service, Iowa State College, 1939.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.