Marinow, K. Wild, Haughty and Menacing Highlanders: Bulgarians and Mountains in the Context of Byzantine-Bulgarian Armed Conflicts. In The Bulgarian State in 927-969. The Epoch of Tsar Peter I: No. XXXIV; Leszka, M. J., Ed.; , Series Ed.; Byzantina Lodziensia; Lodz University Press: Poland, 2018; pp. 287-301. https://doi.org/10.18778/8142-115-7.16.