Y. Al-Khayyat, B., and S. S. Al-Dabbagh. “Using Fuzzy Logic to Construction of Expert Computer Model for Forecast of Compressive Strength of the Portland Cement”. AL-Rafidain Journal of Computer Sciences and Mathematics, vol. 2, no. 2, Dec. 2005, pp. 29-49, doi:10.33899/csmj.2005.164087 .