Tchernev, G., H. Mangarov, and A. A. Chokoeva. “Khan Krum - ʺThe Fearsomeʺ: A Noble Bulgarian With Iris-Fibroma?”. Open Access Macedonian Journal of Medical Sciences, vol. 5, no. 5, Aug. 2017, pp. 696-7, doi:10.3889/oamjms.2017.156.