Comment on “Thermal-diffusion and diffusion-thermo effects on mixed free-forced convective flow and mass transfer over an accelerating surface with a heat source in the presence of suction and blowing in the case of variable viscosity” by M. A. Seddeek (Acta Mech. 172, 83–94, 2004) and on “Finite element method for the effects of chemical reaction, variable viscosity, thermophoresis and heat generation/absorption on a boundary-layer hydromagnetic flow with heat and mass transfer over a heat surface” by M. A. Seddeek (Acta Mech. 177, 1–18, 2005)