The moment of truth [documento electrónico] : a portrait of the success of the discount MVNO's / ed. by Strand Consult
The demand for future mobile communications markets and services in Europe [documento electrónico] / Simon Forge, Colin Blackman and Erik Bohlin
Media system of Portugal [documento electrónico] / Carlos Landim
Listagem dos lugares de Portugal e respectiva população residente / Instituto Nacional de Estatística