(1990). The Systems thinker.
Lua i Stíl Chicago (17ú heag.)The Systems Thinker. 1990.
Lua MLA (9ú heag.)The Systems Thinker. 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.
Lua APA (7ú heag.)