SCHWITZGEBEL, R. K. Changing Human Behavior: Principles of planned intervention. McGraw-Hill Book Company.
Lua i Stíl Chicago (17ú heag.)SCHWITZGEBEL, Ralph K. Changing Human Behavior: Principles of Planned Intervention. McGraw-Hill Book Company.
Lua MLA (8ú heag.)SCHWITZGEBEL, Ralph K. Changing Human Behavior: Principles of Planned Intervention. McGraw-Hill Book Company.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.