Gergova, D., Iliev, I. and Rizzo, V. 1995. Evidence of a seismic event on Thracian tombs dated to the Hellenistic period (Sveshtari, Northeastern Bulgaria). Annals of Geophysics. 38, 5-6 (Nov. 1995). DOI:https://doi.org/10.4401/ag-4089.