Number portability : strategies for market, technical and regulatory success / David Rogerson, Helena Grunfeld
1996 Kagan's european television / ed. Kagan World Media
As grandes conferências das Nações Unidas : nova abordagem ao desenvolvimento(do Cairo a Beijing) / Sónia Melo e Castro
Purchasing power parities and real expenditures : EKS results 1993 / Organisation for Economic co-Operation and Development