1. International Energy Outlook 2021;U.S. Energy Information Administration,2021
2. Energy Balance Sheets 2017 Data,2019
3. Eurostat Eurostat Data Browser
https://ec.europa.eu/eurostat/en/
4. Energy Data 2020 Edition,2020
5. Wind Energy in Europe 2020 Statistics and the Outlook for 2021–2025,2021