Dobrev, N., E. Koleva-Rekalova, and R. Nankin. “The Sarmatian Carbonate Tempestites from Kaliakra Cape (NE Bulgaria) – a Real Risk to Its Stability”. Proceedings of the Bulgarian Academy of Sciences, vol. 75, no. 3, Mar. 2022, pp. 396-04, doi:10.7546/CRABS.2022.03.09.