E. Arif, G., 		Jaafar, S., & 		M. Abdullah, ,.
(2019).
 Using Least squares methods and nonlinear regression Methods to Calculate the Approximate Value of Ionicity in Terms of the Energy Gap.
<em>Tikrit Journal Of Pure Science, 24</em>(5), 97-104.
doi:10.25130/j.v24i5.874