iTV revenue streams and business models : balancing ARPU and future growth to 2006 / ed. Datamonitor
OECD science, technology and industry scoreboard / Organisation for Economic co-Operation and Development
Gestão por processos, da estratégia à melhoria contínua das organizações / Ed. Iberogestão
Top 10 fixed-line operators in Western Europe [documento electrónico] / Linda Unden