1. STN AnaVist™, version 1.1 http://www.stn-international.de/stninterfaces/stnanavist/stn_anavist.html.
2. Who will fund America's energy future (2006) by Interstate Oil & Gas Compact Commission, http://www.iogcc.state.ok.us/.
3. Energy subsidies in the European Union, a brief overview, European Environment Agency, Copenhagen 2004.
4. Energy in Framework Programme 7 (FP7), Stefan Müller, January 2007.