1. http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=URISERV:em0045&from=EN&isLegissum=true, as of 28.05.2016.
2. http://europa.eu/legislation_summaries/energy/external_dimension_enlargement/l27037_en.htm, as of 28.05.2016.
3. http://europa.eu/documents/comm/green_papers/pdf/com2006_105_en.pdf , as of 28.05.2016.
4. http://ec.europa.eu/clima/policies/strategies/2020/index_en.htm , as of 28.05.2016.
5. http://www.c2es.org/international/negotiations/cop21-paris/summary , as of 28.05.2016.