“…Rap et al [23], Ravnik and Škerget [25,26], Li et al [18] and Pettres and Lacerda [22] considered the case of isotropic diffusion and variable coefficients (inhomogeneous media). Recently Azis and co-workers had been working on steady state problems of anisotropic inhomogeneous media for several types of governing equations, for examples [5,32] for the modified Helmholtz equation, [4,14,24,30,27,11,17] for the diffusion convection reaction equation, [29,8,13,16] for the Laplace type equation, [10,2,20,21,15] for the Helmholtz equation.…”