%0 Journal Article %A %D 2018 %J International Journal of Sustainable Energy and Environmental Research %@ 2306-6253 %V 7 %N 2 %P 53-64 %T Determination of Refractivity Gradient and Modified Refractivity Gradient for Cross River State %M 10.18488/journal.13.2018.72.53.64 %U http://www.pakinsight.com/archive/13/06-2018/2