Premium rate services in the SMS era / Chris Dineen
E-commerce and development report 2002 / United Nations Conference on Trade and Development
Proceedings of the EIPub2003, the 7th ICCCP/IFIP International Conference on Electronic Publishing / ed. Sely Maria de Souza Costa ...[et. al]
Serviços de telecomunicações em Portugal : análise e previsões, 2002-2007 / Gabriel Coimbra