General tariff principles : charging and accounting in international telecommunication services: recommendations of the D series / International Telecommunication Union
General tariff principles : charging and accounting in international telecommunication services: Series D recommendations / International Telecommunication Union
Comparação dos preços da electricidade na União Europeia / Entidade Reguladora do Sector Eléctrico
Tarificação nas telecomunicações [texto policopiado] / António Nogueira Leite, Carmo Seabra