APA-referens (7:e uppl.)

Hayler, R., & Nichols, M. (2005). What is six sigma process management? (First edition.). McGraw-Hill Education.

Chicago-referens (17:e uppl.)

Hayler, Rowland, och Michael Nichols. What Is Six Sigma Process Management? First edition. New York: McGraw-Hill Education, 2005.

MLA-referens (9:e uppl.)

Hayler, Rowland, och Michael Nichols. What Is Six Sigma Process Management? First edition. McGraw-Hill Education, 2005.