1. IEA PVPS. Snapshot of global PV markets 2014–2015.
2. GWEC (Global Wind Energy Council). Global wind statistics 2014, 2015. http://www.gwec.net/wp-content/uploads/2015/02/GWEC_GlobalWindStats2014_FINAL_10.2.2015.pdf.
3. Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC. OJ L 140, 5.6.2009, p. 16–62. http://data.europa.eu/eli/dir/2009/28/oj.
4. The Federal Ministry for Economic Affairs and Energy (BMWi). The energy of the future: Fourth energy transition monitoring report-summary. Berlin, 2016. https://www.bmwi.de/BMWi/Redaktion/PDF/V/vierter-monitoring-bericht-energie-der-zukunft-englische-kurzfassung,property=pdf,bereich=bmwi2012,sprache=de,rwb=true.pdf.
5. The Danish climate policy plan: towards a low carbon society;The Danish Government,2013