“Polish Captain Andrzej Okun’s Role in the Military Campaigns Against the Ukrainian Cossacks (1648 – beginning of the 50s of the ХVII century)”, HoUS, vol. 21, pp. 21–29, Sep. 2016, Accessed: Oct. 25, 2026. Available: https://periodicals.karazin.ua/uahistory/article/view/6049