There's some stuff by history teachers there...um we got some photocopied thingos for our task.
Vietnam: the history, the tactics, MacDonald and co, London
Vietnam: The anatomy of a war, Kolko
War and Aftermath in Viet, Brown
Vietnam the Thousand Day War MacClear
Yeah I went to that site and basically just printed off all the notes. They're good. Also maybe do a general search on google and find quotes from presidents (LBJ, Nixon etc.) Also the leaders of north vietnamese forces. Don't know if this is relevant to historiography though.