Чугуй, Т. “Rus’, Hungary and the Holy Roman Empire in the International Relations of The Second Third of the 13th Century: Actual Problems of Historiography”. V. N. Karazin Kharkiv National University Bulletin ‘History of Ukraine. Ukrainian Studies: Historical and Philosophical Sciences’, Vol. 28, Oct. 2019, pp. 6-18, doi:10.26565/2227-6505-2019-28-01.