This webpage from De Bono Consulting provides an overview of the six thinking hats and includes a range of free resources including guides and videos. A range of resources, including training programs are also unavailable for purchase.
de Bono Consulting. (2009). Six thinking hats. Retrieved from http://www.debonoconsulting.com/Six_Thinking_Hats.asp
'Six Thinking Hats' is referenced in: