Mohammed W. Alhazmi, Ahmed H. Backar. “Influence of Infill Density and Orientation on the Mechanical Response of PLA+ Specimens Produced Using FDM 3D Printing ”. International Journal of Advanced Science and Technology, Vol. 29, no. 06, May 2020, pp. 3362 -71, http://sersc.org/journals/index.php/IJAST/article/view/14078.