Telecom Italia is trying to line up a loan worth up to 20 billion euros ($21.79 billion) as part of its defence against Olivetti SpA's hostile offer, banking sources said yesterday. Telecom Italia, if it managed to raise the money, would probably use it for a share buyback or a special dividend to defend itself against Olivetti.Olivetti last month launched a $58 billion takeover bid for the former state-owned group which is five-times its own size. It plans to part-finance the takeover with a €22.5 billion loan currently being arranged.