Er zijn nog geen Nederlandstalige annotaties. Hier volgen annotaties in het Engels.
- http://bulgariancastles.com/bg/node/2187
- https://www.academia.edu/30948823/%D0%90%D0%9D%D0%A2%D0%98%D0%A7%D0%9D%D0%98_%D0%98_%D0%A1%D0%A0%D0%95%D0%94%D0%9D%D0%9E%D0%92%D0%95%D0%9A%D0%9E%D0%92%D0%9D%D0%98_%D0%9A%D0%A0%D0%95%D0%9F%D0%9E%D0%A1%D0%A2%D0%98_%D0%92_%D0%A6%D0%95%D0%9D%D0%A2%D0%A0%D0%90%D0%9B%D0%9D%D0%90_%D0%A1%D0%A2%D0%90%D0%A0%D0%90_%D0%9F%D0%9B%D0%90%D0%9D%D0%98%D0%9D%D0%90_%D0%86