R.Z. Valiev and T.G. Langdon, Achieving exceptional grain refinement through severe plastic deformation: New approaches for improving the processing technology, Metallic Materials Transection A, 42 (2011) 2942-2951.
 A.Azushima, R. Kopp, A. Korhonen, D.Y. Yang, F. Micari, G.D. Lahoti, P. Groche, J. Yanagimoto, N. Tsuji, A. Rosochowski and A. Yanagida, Severe plastic deformation (SPD) processes for metals, CIRP Annual Manufacturing and Technology, 57 (2008) 716-735.
 Y. Estrin and A. Vinogradov, Extreme grain refinement by severe plastic deformation: a wealth of challenging science, Acta Mateillia, 61 (2013) 782-817.
 R.Z. Valiev, R.K. Islamgaliev and I.V. Alexandrov, Bulk nanostructured materials from severe plastic deformation, Progress in Materials Science, 45 (2000) 103-189.
 M. Shahbaz, N. Pardis, R. Ebrahimi and B. Talebanpour, A novel single pass severe plastic deformation technique: Vortex extrusion, Materials Science and Engineering A, 530 (2011) 469-472.
 M. Shahbaz, R. Ebrahimi, H.S. Kim, Streamline Approach to Die Design and Investigation of Material Flow in Vortex Extrusion Process, Applied Mathematical Modelling, 40 (2016) 3550–3560.
 M. Shahbaz, N. Pardis, J.G. Kim, R. Ebrahimi, H.S. Kim, Experimental and finite element analyses of plastic deformation behavior in vortex extrusion, Materials Science and Engineering A, 674 (2016) 472–479.
 Y. Beygelzimer, Grain refinement versus voids accumulation during severe plastic deformations of polycrystals: mathematical simulation, Mechanics of Materials, 37 (2005) 753-767.
 M.I. Latypov, I.V. Alexandrov, Y. Beygelzimer, S. Lee and H.S. Kim, Finite element analysis of plastic deformation in twist extrusion, Computational Materials Science, 60 (2012) 194-200.
 M.I. Latypov, M.G. Lee, Y. Beygelzimer, R. Kulagin and H.S. Kim, On the simple shear model of twist extrusion and its deviations, Metals and Materials International, 21 (2015) 569-579.
 Y. Beygelzimer, R. Kulagin, M.I. Latypov, V. Varyukhin and H.S. Kim, Off-axis twist extrusion for uniform processing of round bars, Metals and Materials International, 21 (2015) 734-740.
 B. Avitzur, Metal forming: processes and analysis, Original ed., McGraw-Hill Book Co., Reprint with revisions and corrections, New York (1979).
 M. Seyed Salehi, N. Anjabin and H.S. Kim, An upper bound solution for twist extrusion process, Metals and Materials International, 20 (2014) 825-834.
 S. Khoddam, A. Farhoumand and P.D. Hodgson, Upper-bound analysis of axi-symmetric forward spiral extrusion, Mechanics of Materials, 43 (2011) 684-692.
 S.F. Hoysan and P.S. Steif, A streamline-based method for analyzing steady state metal forming processes, International Journal of Mechanical Science, 34 (1992) 211-221.
 N.R. Chitkara and K.F. Celik, A generalised CAD/CAM solution to the three-dimensional off-centric extrusion of shaped sections: analysis, International Journal of Mechanical Science, 42 (2000) 273-294.
 N.R. Chitkara and K. Abrinia, A generalized upper-bound solution for three-dimensional extrusion of shaped sections using CAD/CAM bilinear surface dies, Processing in 28th. International Matador Conference, 18, April (1990).
 R. Ponalagusamy, R. Narayanasamy and P. Srinivasan, Design and development of streamlined extrusion dies a Bezier curve approach, Journal of Materials and Processing Technology, 161 (2005) 375-380.
 K. Narooei and A. Karimi Taheri, A new model for prediction the strain field and extrusion pressure in ECAE process of circular cross section, Applied Mathematical Modelling, 34 (2010) 1901-1917.
 Y. Beygelzimer, D. Orlov, V. Varyukhin, A new severe plastic deformation method: Twist Extrusion/Ultrafine Grained Materials II. Proceedings of a symposium held during the 2002 TMS Annual Meeting I Seattle, Washington, February 17-21, 2002/ Ed. by Y.T. Zhu, T.G. Langdon, R.S. Mishra, S.L. Semiatin, M.J. Saran, T.C. Lowe, TMS, (2002) 297-304.
 Y. Beygelzimer, A. Reshetov, S. Synkov, O. Prokof'eva, R. Kulagin, Kinematics of metal flow during twist extrusion investigated with a new experimental method. Journal of Materials Processing and Technology, 209 (2009) 3650-3656.