1. The environment is free: The quality analogy
2. Çöp(m)adam Çöp(m)adam available at:http://www.copmadam.com May 7 2020.
3. DeesJ.G. The meaning of ‘Social Entrepreneurship' available at:http://www.fuqua.duke.edu/centers/case/documents/Dees_SEdef.pdf May 30 2001.
4. INSTITUTIONS AND MARKETS IN A DYNAMIC WORLD