Buchan, D. (2009): Energy and Climate Change: Europe at the Crossroads, 20-78.

Buchan, D.; Keay, M. (2015): Europe´s Long Energy Journey: Towards an Energy Union? 32-62.    

Supplementary sources: 

EP (2016): Understanding electricity markets in the EU. http://www.easyres-project.eu/wp-content/uploads/2019/02/understanding-elecricity-markets-in-the-eu.pdf

IEA (2014): European Union – 2014 Review. IEA, 101-148.