Sargsyan, Tigran A. “REGIONAL CHARACTERISTICS, PRINCIPLES AND PERSPECTIVES OF EUROPE’S EXTERNAL ENERGY SUPPLY”. Proceedings of the YSU C: Geological and Geographical Sciences, vol. 57, no. 1-2 (260), July 2023, pp. 53-60, doi:10.46991/PYSU:C/2023.57.1-2.053.