1. Mapping and analyses of the current and future (2020–2030) heating/cooling fuel deployment (fossil/renewables), EUROPEAN COMMISSION DIRECTORATE-GENERAL FOR ENERGY https://ec.europa.eu/energy/sites/ener/files/documents/Report%20WP2.pdf
2. T. Nowak, Heat Pumps, Integrating technologies to decarbonize heating and cooling (European Copper Institute) https://www.ehpa.org/fileadmin/user_upload/White_Paper_Heat_pumps.pdf
3. Mapping and analyses of the current and future (2020–2030) heat-ing/cooling fuel deployment (fossil/renewables) – EUROPEAN COMMISSION DIRECTORATE-GENERAL FOR ENERGY https://ec.europa.eu/energy/sites/ener/files/documents/Report%20WP1.pdf
4. European Directive EU2019/944, Clean Energy for all Europeans. https://ec.europa.eu/energy/topics/energy-strategy/clean-energy-all-europeans_en
5. J. Fisher, Thyssenkrupp is the first to enable conversion of existing elevators into net-zero energy units through modernization (Press Release, https://www.thyssenkrupp-elevator.com, 2017)