Abdel Khalek Awad, Nadia, AND 		Khattab Omar, Boshra.
" The style of positive and negative thinking and its relation to the psychological hardness of university students" <em>Journal of Tikrit university for humanities - مجلة جامعة تكريت للعلوم الانسانية</em> [Online], Volume 24 Number 11 (1 April 2019)