1. European Commission: Communication from the Commission of 12 December 2006 on a European Programme for Critical Infrastructure Protection, COM (2006) 786 Final, Brussels, Belgium (2006)
2. European Commission: Proposal for a Directive of the Council on the Identification and Designation of European Critical Infrastructure and the Assessment of the Need to Improve Their Protection, COM (2006) 787 Final, Brussels, Belgium (2006)
3. Ministry of the Interior and Kingdom Relations: National Risk Assessment Method Guide 2008, The Hague, The Netherlands (2008)
4. U.S. Department of Homeland Security: National Infrastructure Protection Plan 2009, Washington, DC (2009)
5. Public Safety and Emergency Preparedness Canada: Selection Criteria to Identify and Rank Critical Infrastructure Assets, Ottawa, Canada (2004)