Polyvyannyy, D. (2019). Dynasticity in the Second Bulgarian Tsardom and its Manifestations in Medieval History Writing. Studia Ceranea. Journal of the Waldemar Ceran Research Centre for the History and Culture of the Mediterranean Area and South-East Europe, 9, 351-365. https://doi.org/10.18778/2084-140X.09.19 .
″State and Church in the XIII century, Emil Dimitrov (general editor). Synodik of tsar Boril″, (Translated from Old Bulgarian by Anna Maria Totomanova) [1]
″State and church in the XIII century, Emil Dimitrov (general editor), CORRESPONDENCE OF THE BULGARIANS WITH POPE INOCENTIUS III.″ (Translated from Latin by Mikhail Voynov, Ivan Duychev) [2]