References
- EU ETSI, ETSI SR 002 299: Emergency Communications: European Regulatory Principles. 2004
- EU ETSI, ETSI SR 002 180: Requirements for Communication of Citizens with Authorities/Organizations in Case of Distress, 2004
- ITU. Handbook on Emergency Telecommunication, 2003
- ITU-T. ETS Work in ITU-T Study Group 16. 2005
- NCS. Public Switched Network Security Assessment Guidelines. 2002