National Fertilizer Development Center. (1973). Fertilizer trends. Washington, D.C: National Fertilizer Development Center.
استشهاد بنمط شيكاغوNational Fertilizer Development Center. Fertilizer Trends. Washington, D.C: National Fertilizer Development Center, 1973.
MLA استشهادNational Fertilizer Development Center. Fertilizer Trends. Washington, D.C: National Fertilizer Development Center, 1973.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.