K. Marinow, „Wild, Haughty and Menacing Highlanders: Bulgarians and Mountains in the Context of Byzantine-Bulgarian Armed Conflicts”, w The Bulgarian State in 927-969. The Epoch of Tsar Peter I: No. XXXIV, M. J. Leszka, Red. Poland: Wydawnictwo Uniwersytetu Łódzkiego, 2018, s. 287–301. doi: 10.18778/8142-115-7.16.