مهدي يونس الخفاجي وصف. 2010. “The Effect of Using Learning Cycle on the Acquisition of Biological Concepts by First Year Students Science Department/College of Basic Education- Mosul University”. College of Basic Education Research Journal 9 (4):101-30. https://moss.uomosul.edu.iq/index.php/berj/article/view/38206.