1. Digital cellular telecommunications system (Phase 2+); Interworking between Phase 1 infrastructure and Phase 2 Mobile Stations (MS). http://www.etsi.org/deliver/etsi_ts/101600_101699/101644/05.01.00_60/ts_101644v050100p.pdf
2. GSM security map. http://gsmmap.org/
3. How the NSA pinpoints a mobile device. http://apps.washingtonpost.com/g/page/world/how-the-nsa-pinpoints-a-mobile-device/645/ . Accessed 30 Oct 2015
4. Digital cellular telecommunications system (Phase 2+); Location Services (LCS); Mobile Station (MS) - Serving Mobile Location Centre (SMLC) Radio Resource LCS Protocol (RRLP), 3GPP TS 04.31 version 8.18.0 (2007). http://www.etsi.org/deliver/etsi_ts/101500_101599/101527/08.18.00_60/ts_101527v081800p.pdf
5. Egypt tries to control the use of GPS by banning except with individual licences (2008). http://www.balancingact-africa.com/news/en/issue-no-429/top-story/egypt-tries-to-contr/en