1. Directive 91/271/EEC concerning urban waste-water treatment.
2. Directive 2000/60/EC establishing a framework for the Community action in the field of water policy.
3. ARERA Relazione Annuale sullo stato dei servizi e sull’attività svolta 2018. In Italian.
4. EPRI, Electricity use and management in the municipal water supply and wastewater industries, 2013.
5. Fundaciòn OPTI e IDAE, Estudio de prospectiva: consumo energético en el sector del agua, 2010.