M. Yahya, O., B. A. Ahmed, and I. Thanoon. “Ultrasound-Assisted One-Pot Synthesis of Dihydropyrimid-2-one/Thiones Catalyzed by Zirconyl Chloride Hexahydrate”. Journal of Education and Science (JES), vol. 26, no. 5, Dec. 2013, pp. 154-9, doi:10.33899/edusj.2013.163065.