Columbia subject headings:
Bulgaria--History--681-1018.
Byzantine Empire--History.
Inscriptions, Bulgaro-Turkic--Bulgaria.
Harvard subject headings:
Bulgaria--History--681-1018.
Byzantine Empire--History.
Inscriptions, Bulgaro-Turkic--Bulgaria.
Princeton subject headings:
Bulgaria--History--681-1018.
Byzantine Empire--History--527-1081.
Inscriptions, Bulgaro-Turkic--Bulgaria.