1. APX, 2014. Information on the Web Page of APX – Elbas Intraday Trading System. URL 〈http://www.apxgroup.com/services/trading-platforms/elbas-intraday-trading-system/〉 (accessed 15.05.2015).
2. APX, 2015. Information on the Web Page of APX – APX Power UK. URL 〈https://www.apxgroup.com/trading-clearing/apx-power-uk/〉 (accessed 15.05.2015).
3. Borsche, T., Andersson, G., 2014. A review of demand response business cases. In: Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), 2014 IEEE PES, pp. 1–6.
4. Bundesregierung, 2009. Verordnung zur Weiterentwicklung des bundesweiten Ausgleichsmechanismus (AusglMechV) mit Begründung – Drucksache 16/13188. Draft of Directive, German Government. URL 〈http://dipbt.bundestag.de/doc/btd/16/131/1613188.pdf〉 (accessed 15.05.2015).
5. Connolly, D., 2010. A Review of Energy Storage Technologies: For the Integration of Fluctuating Renewable Energy. Report. Aalborg Universitet, Version 4.1. URL 〈http://vbn.aau.dk/files/100570335/Energy_Storage_Techniques_v4.1.pdf〉 (accessed 15.05.2015).