GJUZELEV, Vassil. The Fourth Crusade and Its Consequences for the Medieval Bulgaria: Kaloyan, the Latins and the Greeks (1204–1207). Studia Ceranea, Poland, v. 3, p. 29–37, 2013. DOI: 10.18778/2084-140X.03.02. Disponível em: https://www.czasopisma.uni.lodz.pl/sceranea/article/view/5433. Acesso em: 8 aug. 2026.