Regras técnicas das instalações eléctricas de baixa tensão / Imprensa Nacional - Casa da Moeda
Facts & figures [documento electrónico] : about European Telecoms Operators / European Telecommunication Network Operators'Association
Mobile broadband operator strategies in Western Europe [documento electrónico] / Steven Hartley
IPTV benchmark [documento electrónico] : Western Europe / Michele Mackenzie, Charlie Davis