WASET
Hekmatpanah, M. , Sadroddin, M. , Shahbaz, S. , Mokhtari, F. , Fadavinia, F. (2008), 'Six Sigma Process and its Impact on the Organizational Productivity', World Academy of Science, Engineering and Technology, Open Science Index 19, International Journal of Economics and Management Engineering, 2(7), 731 - 735.