Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 37 No. 2 2011 07 15 EXACT SOLUTIONS FOR FLOW OF A SISKO FLUID IN PIPE49 60 en N. MOALLEMI I. SHAFIEENEJAD A. NOVINZADEH 2008 10 05 Non-Newtonian uid nonlinear equation Sisko model homotopy perturbation method (HPM)