Valdes, A., & Zietz, J. (1980). Agricultural protection in OECD countries: Its cost to less - developed countries. International Food Policy Research Institute.
استشهاد بنمط شيكاغوValdes, Alberto, و Joachim Zietz. Agricultural Protection in OECD Countries: Its Cost to Less - Developed Countries. Washington, D C: International Food Policy Research Institute, 1980.
MLA استشهادValdes, Alberto, و Joachim Zietz. Agricultural Protection in OECD Countries: Its Cost to Less - Developed Countries. International Food Policy Research Institute, 1980.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.