Връзки https://ec.europa.eu/dgs/energy/index_en.htmhttps://www.acer.europa.eu/Gas/Pages/default.aspxhttps://www.entsog.eu/https://www.me.government.bg/bghttp://www.dker.bg/https://www.bulgargaz.bg/https://www.bulgartransgaz.bg/bg