1. C. Rauwendael: ‘Polymer extrusion’; 2001, München, Carl Hanser Verlag.
2. R. B. Bird, R. C. Armstrong and O. Hassager: ‘Dynamics of polymeric liquids’, 2nd edn, Vol. I; 1987, New York, John Wiley & Sons.
3. C. W. Macosko: `Rheology: principles, measurements, applica-tions'; 1994, New York, John Wiley & Sons.
4. A. Y. Malkin and A. I. Isayev: `Rheology: concepts, methods and applications'; 2005, Norwich, NY, Chemtec.
5. Secondary motions in straight and tapered channels: Experiments and three-dimensional finite element simulation with a multimode differential viscoelastic model