1. International Energy Agengy. World Energy Outlook 2012, Paris; 2012.
2. Commission of the European Communities. Energy roadmap 2050, Luxembourg; 2012. http://ec.europa.eu/energy/publications/doc/2012_energy_ roadmap_2050_en.pdf (accessed November 6, 2013).
3. European Commission. Energy statistics – prices; 2013. http://epp.eurostat.ec.europa.eu/portal/page/portal/energy/data/main_table s (accessed November 6, 2013).
4. Schlomann B, Fleiter T, Hirzel S, Arens M, Rohde C, Eichhammer W, Cebulla F, Elsland R, Fehrenbach D, Singer N, Gerspacher A, Idrissova F, Jochem E, Mai M, Reitze F, Toro FA, Bachmann J, Wittich K, Hassan A. Energy consumption and CO2 emissions of industrial process technologies – saving opportunities, barriers and tools [original title: Energieverbrauch und CO2-Emissionen industrieller Prozesstechnologien – Einsparpotenziale, Hemmnisse und Instrumente]; 2013.
5. Müller E, Krones M, Strauch J. Methodical approach to identify energy efficiency measures in factory planning based on qualitative analysis. In: Azevedo A, editor. Advances in sustainable and competitive manufacturing systems – Lecture notes in mechanical engineering. Heidelberg, New York: Springer International Publishing; 2013. p. 1627-1637.