The Virtual Resource Centre for Knowledge about Europe (CVCE) is a resource centre for the study of the EU. It contains links to multimedia resources relating to the history of European integration, including media clips of key historical events: http://www.cvce.eu/home
The Europa website provides an overview of the Treaty Establishing the European Coal and Steel Community.
The Europa website offers an overview of the Treaty Establishing the European Atomic Energy Community (Euratom):
A translation of the Spaak report of 1956, which proposed a blueprint for the development of a common market, can be found at the University of Pittsburgh's Archives of European Integration.
The Western European Union (WEU) was set up in 1955 after the collapse of the European Defence Community (EDC) negotiations. Although the organisation was wound down and dissolved in 2011, its archived website offers a brief overview of its history and links to key documents.