BREYFOGLE FORREST W. (2003). IMPLEMENTING SIX SIGMA (2ND ED.). JOHN WILEY AND SONS INC.
Lua i Stíl Chicago (17ú heag.)BREYFOGLE FORREST W. IMPLEMENTING SIX SIGMA. 2ND ED. HOBOKEN: JOHN WILEY AND SONS INC, 2003.
Lua MLA (9ú heag.)BREYFOGLE FORREST W. IMPLEMENTING SIX SIGMA. 2ND ED. JOHN WILEY AND SONS INC, 2003.
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