Williams, B., & Hummelbrunner, R. (2009). Systems concepts in action: A practitioner's toolkit. Stanford Business Books.
Lua i Stíl Chicago (17ú heag.)Williams, Bob, agus Richard Hummelbrunner. Systems Concepts in Action: A Practitioner's Toolkit. Stanford, Calif.: Stanford Business Books, 2009.
Lua MLA (9ú heag.)Williams, Bob, agus Richard Hummelbrunner. Systems Concepts in Action: A Practitioner's Toolkit. Stanford Business Books, 2009.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.