Comment on “Effects of the slip boundary condition on non-Newtonian flows in a channel” [Commun. Nonlinear Sci. Numer. Simul. 14 (2009) 1377–1384]

Recently, Ellahi [1] discussed the slip effects on the flows of an Oldroyd 8-constant fluid using the homotopy analysis method. Crucial flaws in [1] are pointed out in this comment. The present paper provides an exact solution and a numerical solution by shooting method using Runge–Kutta algorithm of the flow problems considered in [1] with the correct nonlinear boundary conditions.