Khalaf Ibrahim, Z., Jassim Hamash, I., & Mahmoud Khalaf, Y. 2019 Mar 30. The impact of the model of collective investigation in the collection of history material among the fifth grade students and the development of their reasoning thinking / Directorate General of Kirkuk Education. Journal of Tikrit university for humanities - مجلة جامعة تكريت للعلوم الانسانية. [Online] 24:1