Al-Baldawi, Ammar, Shatha Muallah, and Olaf Wünsch. “Thermo-Rheological Investigation and Modeling of the Shear Viscosity of Polypropylene above the Melting Temperature”. Al-Khwarizmi Engineering Journal 9, no. 4 (December 31, 2013): 12- 23. Accessed November 29, 2019. http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/181.