1. BT Group Archives — http://www.btplc.com/Thegroup/BTsHistory/BTgrouparchives/index.htm
2. E.164 Numbering Scheme — http://www.itu.int/itudoc/itu-t/oblists/icc/index.html
3. Swale R (Ed): ‘Voice over IP: systems and solutions’, The Institution of Electrical Engineers, pp 21–22 (2001).
4. 3G Partnership Programme — http://www.3gpp.org/
5. Toronto Star: ‘Consumer Electronics Association’, (August 2003).