European Commission. Directorate-General for Energy and Transport. (2005). Report on the green paper on energy: Four years of European initiatives. Office for Official Publications of the European Communities.
Cita Chicago (17th ed.)European Commission. Directorate-General for Energy and Transport. Report on the Green Paper on Energy: Four Years of European Initiatives. Luxembourg: Office for Official Publications of the European Communities, 2005.
Cita MLA (9th ed.)European Commission. Directorate-General for Energy and Transport. Report on the Green Paper on Energy: Four Years of European Initiatives. Office for Official Publications of the European Communities, 2005.
Atenció: Aquestes cites poden no estar 100% correctes.