Чугуй, Т. 2019. 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’. 28, (Oct. 2019), 6-18. DOI:https://doi.org/10.26565/2227-6505-2019-28-01.