Gilbert, R. (1996). The thinking option: For improving business performance. Prentice Hall.
Lua i Stíl Chicago (17ú heag.)Gilbert, Roy. The Thinking Option: For Improving Business Performance. Sydney: Prentice Hall, 1996.
Lua MLA (9ú heag.)Gilbert, Roy. The Thinking Option: For Improving Business Performance. Prentice Hall, 1996.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.