1. European Commission, On a European programme for critical infrastructure protection. European Comission Green Book, Official Journal of the European Communities, Brussels, 2005.
2. Council European Union, On the identification and designation of European critical infrastructures and the assessment of the need to improve their protection, Council Directive CE/114, 2008.
3. US Department of Homeland Security, NIPP – National Infrastructure Protection Plan, Washington DC, 2009.
4. U.S. Department of Homeland Security, Government facilities critical infrastructure and key resources sector-specific plan as input to the national infrastructure protection plan, Washington DC, 2007.
5. U.S. Department of Homeland Security, Directive 7: Critical Infrastructure Identification, Prioritization, and Protection, Washington DC, 2003.