1. Abdullahi U. Usman, Hassan S. Abdulkadir and Kabiru Tukur, 2015, Application of
2. Dummy Variables in Multiple Regression Analysis, Jodhpur National University,
3. Jodhpur, Rajasthan, India. International Journal of Recent Scientific Research Vol. 6,
4. Issue, 11, pp. 7440-7442, November, 2015.
5. David G. Kleinbaum, Lawrence L. Kupper, Azhar Nizam, Eli S. Rosenberg, 2013,