Shapovalov, Sergey. “Settlement Process on The Black Sea Northeastern Coast In the Context of Frederick Turner’s Frontier Concept (1830‑1850s)”. Journal of Frontier Studies 10, no. 1 (February 12, 2025): 167-184. Accessed May 24, 2025. https://www.jfs.today/index.php/jfs/article/view/602.