Amer Jaber, dr., & Zahawy, S. (2011). Measuring and Analysis of Productivity Efficiency by Using Cobb – Douglas Production Function in the State Company for Drug Industries in Samarras during (1986 – 2006). TANMIYAT AL-RAFIDAIN, 33(103), 26–45. https://doi.org/10.33899/tanra.2011.161941