some initial thoughts: 1. what (even approximate) date do you consider coverage to have started? (i.e. the Munich Crisis, invasion of Poland, 12-7-41?) This affects the two NBC networks Red and Blue. 2. "The Golden Web" by Erok Barnouw 3. NBC:LOC has their documents as well as the trove of broadcast recordings 4. CBS: I don't know where its corporate historical files are, but try The Paley Center here in NYC. Google searches should include Ed Murrow, William L. Shirer and Larry LeSueur 5.