5Giokas D I, Pentzaropoulos G C. Efficiency ranking of the OECD member states in the area of telecommunications: A composite AHP/DEA study[J]. Telecommunications Policy, 2008(32): 672-685.
6Godoe H. Innovation regimes, R&D and radical innovations in telecommunications[J]. Research Policy, 2000(29): 1033-1046.