1. AEEG (the Italian Regulatory Authority for Electricity and Gas), 2008. Terzo Rapporto Annuale sul Meccanismo dei Titoli di Efficienza Energetica. Situazione al 31 Maggio 2008 (3rd annual report of the White Certificates at 31st May 2008). URL: 〈http://www.autorita.energia.it/allegati/pubblicazioni/eerapporto_08.pdf〉.
2. Bertoldi, P., Rezessy, S., 2005. European Energy Service Companies Status Report 2005. Office for Official Publications of the European Communities, Luxembourg
3. Energy service companies in European countries: current status and a strategy to foster their development;Bertoldi;Energy Policy,2006
4. Bertoldi P. et al., 2007. Latest Development of Energy Service Companies across Europe. A European ESCO Update. Office for Official Publications of the European Communities, Luxembourg
5. Dupont, M., Adnot, J., 2004. Investigation of actual energy efficiency content of “energy services” in France. In: Bertoldi, P., Atanasiu, B. (Eds.), Proceedings of International Conference on Improving Energy Efficiency in Commercial Buildings (IEECB’04), Frankfurt (Germany), 21–22 April 2004. Office for Official Publications of the European Communities, Luxembourg.