00550nam a2200181 a 45000010005000000030005000050050017000100080041000270400020000681000017000882450088001052500011001932600050002043000011002544900022002656500034002876500047003212553CDMR20131107101321.0130130s1961||||||||||||||||||||||||||||d aCDMRbcatcCDMR1 aLaffay, Jean14aLes télécommunicationsb: télégraphe, téléphone, radiocpas Jean Laffay a2a ed. aParisc1961bPresses Universitaires de France a127 p.0 aQue sais-je?v33504aSistemes de telecomunicació04aComunicacióxInnovacions tecnològiques