Kirilova, K. . (2023) “OPTIMAL GEOPOTENTIAL MODELS OF THE EARTH’S GRAVITATIONAL FIELD FOR THE TERRITORY OF SOUTHWESTERN BULGARIA - RILA MOUNTAIN: OPTIMAL GEOPOTENTIAL MODELS OF THE EARTH’S GRAVITATIONAL FIELD FOR THE TERRITORY OF SOUTHWESTERN BULGARIA - RILA MOUNTAIN”, JOURNAL SCIENTIFIC AND APPLIED RESEARCH, 19(1), pp. 67–71. doi: 10.46687/jsar.v19i1.295.