El-Kabeir, S.M.M.M.M., El-Hakiem, M.A.A. and Rashad, A.M.M. (2007) “Natural Convection from a Permeable Sphere Embedded in a Variable Porosity Porous Medium Due to Thermal Dispersion”, Nonlinear Analysis: Modelling and Control, 12(3), pp. 345–357. doi:10.15388/NA.2007.12.3.14693.