For the architect Wolfgang Frey, the five principles of sustainability relate to ecology, economy, society, vision, and motivation. In his book The Five Finger Principle, Frey illustrates the principles of socially and ecologically sustainable architecture using a wealth of real-world examples. Among others the Frey Architectural Firm presented concepts and projects for sustainable architecture and urban development on behalf of the city of Freiburg at the EXPO 2010 in Shanghai. ukryj opis