Pysar, Nadiia, Dergachova Viktoria, Olena Vynogradova, and Olga Guseva. 2020. “Gross Domestic Product Energy Intensity Level As a Criterion for Evaluating the Energy Security of National Economy”. International Journal of Energy Economics and Policy 10 (4):424-29. https://econjournals.com/index.php/ijeep/article/view/9420.