Ray Subhadrata MPE. (2011). Six Sigma: Controlling & Improving Production Process & Quality. MPE-NMIMS.
Chicago-referens (17:e uppl.)Ray Subhadrata MPE. Six Sigma: Controlling & Improving Production Process & Quality. Mumbai: MPE-NMIMS, 2011.
MLA-referens (9:e uppl.)Ray Subhadrata MPE. Six Sigma: Controlling & Improving Production Process & Quality. MPE-NMIMS, 2011.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.