Abdullah, Mohammed Mahmood. “The Role of Content Marketing in Achieving Customer Happiness An Analytical Study of the Opinions of a Sample of (Apple - Iphone) Users in Three Faculties of Tikrit University”. Tikrit Journal of Administrative and Economic Sciences, vol. 18, no. 59, 2, Sept. 2022, pp. 157-75, doi:10.25130/tjaes.18.59.2.10.