Meeting the challenges of GPRS billing / Katrina Bond, Emily Turnbull; ed. Rachael Beale, Ian Faulkner
Relatório e contas 2001 / REN - Rede Eléctrica Nacional, S.A.
Worldwide approvals99 : London, 22nd-24th November 1999 / org. IBC
Draft Oftel Management Plan 2002/3 : 19 December 2001 / issued by the Director General of Telecommunications