“Polish Captain Andrzej Okun’s Role in the Military Campaigns Against the Ukrainian Cossacks (1648 – beginning of the 50s of the ХVII century)” (2016) V. N. Karazin Kharkiv National University Bulletin History of Ukraine. Ukrainian Studies: Historical and Philosophical Sciences, 21, pp. 21–29. Available at: https://periodicals.karazin.ua/uahistory/article/view/6049 (Accessed: 25 October 2026).