1. 1. Mark O. George (2010). The lean six sigma guide to doing more with less. John Wiley and Sons. p. 261. ISBN 978-0-470-53957-6.
2. 2. Tarek M. Khalil; L. A. Lefebvre; Robert McSpadden Mason (13 August 2001). Management of technology: the key to prosperity in the third millennium : selected papers from the ninth International Conference on Management of Technology. Emerald Group Publishing. pp. 164. ISBN 978-0-08-043997-6. Retrieved 13 February 2012.
3. 3. Eric A. Marks (2008). Service-oriented architecture governance for the services driven enterprise. John Wiley & Sons. p. 271. ISBN 978-0-470-17125-7.
4. 4. James A. Obrien. Management Information Systems (Special Indian Edition ed.). McGraw-Hill Education (India). p. 315. ISBN 978-0-07-062003-2.
5. 5. National Research Council (U.S.). Committee on Materials Science and Engineering: Forging Stronger Links to Users (2000). Materials science and engineering: forging stronger links to users. National Academies Press. p. 139. ISBN 978-0-309-06826-0.