Shakohe, R. “Study the Effect of Adding Materials (Calcine Powder Styropor Granules and Straw) on the Compressive Strength for Material Polyurethane”. Tishreen University Journal -Engineering Sciences Series, vol. 45, no. 1, Mar. 2023, pp. 143-54, https://journal.tishreen.edu.sy/index.php/engscnc/article/view/13725.