Klemeshev, A. P., G. M. Fedorov, and A. G. Manakov. “Baltic Subjects of the Russian Federation Among Border Regions of Russia”. International Journal of Economics and Financial Issues, vol. 5, no. 2S, Nov. 2015, pp. 41-48, https://econjournals.com/index.php/ijefi/article/view/1584.