Friedman, M. (2005). Trying hard is not good enough: How to produce measurable improvements for customers and communities. FPSI Publishing.
Lua i Stíl Chicago (17ú heag.)Friedman, Mark. Trying Hard Is Not Good Enough: How to Produce Measurable Improvements for Customers and Communities. Victoria, B.C.: FPSI Publishing, 2005.
Lua MLA (8ú heag.)Friedman, Mark. Trying Hard Is Not Good Enough: How to Produce Measurable Improvements for Customers and Communities. FPSI Publishing, 2005.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.