The European Commission provides information and official documents on Enlargement at http://ec.europa.eu/enlargement/index_en.htm.

The European External Action Service provides information and official documents on Neighbourhood Policy at http://www.eeas.europa.eu/enp/.

The project website of the research consortium MAXCAP (Maximizing the Integration Capacity of the European Union; 2013–2016) provides access to publications and resources on the EU’s recent and future enlargements at http://userpage.fu-berlin.de/kfgeu/maxcap/index.html

The project website of the research consortium EU-STRAT (2016–2019) provides access to publications and a research database on the relationship between the European Union and the countries in the European Eastern neighbourhood at http://eu-strat.eu.

For a recent video update on EU enlargement (interview with Jean-Claude Juncker), see: https://youtu.be/6A--sqA1KQs, and for an interesting debate on Western Balkan enlargement in the EP: https://www.youtube.com/watch?v=vXVzJ-jrkm0.