Explaining international broadband leadership [documento electrónico] / Robert D. Atkinson, Daniel K. Correa, Julie A. Hedlund
Índice nacional de satisfação do cliente : relatório ICP - ANACOM: 2007 / Manuel Vilares, Pedro Simões Coelho e Susana Esteves
African telecommunication / ICT indicators 2008 : at a crossroads / International Telecommunication Union