B. A. Abbas, A. Ibrahim, and A. T. Andyar. “Optimization of Compressive Strength of Periwinkle Shell Concrete Using Scheffe’s Model”. Journal of Built Environment and Geological Research 10, no. 4 (December 24, 2025). Accessed November 11, 2026. https://africanscholarpub.com/ajbegr/article/view/1045.