Sources:
- Piotr Włodarczak, Stefan Alexandrov:, Early Bronze Age barrows in Upper Thrace, in : From the Steppes to the Balkans Yamna Culture in Upper Thrace, Budapest 2024
- odor Valchev & Adela Sobotkov, Landscape analysis of the Early Bronze Age mounds in the Middle and Lower Tundzha River http://www.sarks.fi/masf/masf_11/MASF11_28_Valchev_Sobotkova.pdf
- Heyd Volker. Yamnaya Groups and Tumuli west of the Black Sea. In: Ancestral Landscape. Burial mounds in the Copper and Bronze Ages (Central and Eastern Europe – Balkans – Adriatic – Aegean, 4th-2nd millennium B.C.) Proceedings of the International Conference held in Udine, May 15th-18th 2008. Lyon : Maison de l'Orient et de la Méditerranée Jean Pouilloux, 2012. pp. 535-555. (Travaux de la Maison de l'Orient et de la Méditerranée. Série recherches archéologiques, 58)