Ilieva, T. K. 1998. [Change of the echinoid fauna across the Cretaceous-Tertiary boundary section in the area of the town Byala, Varna District]. Review of the Bulgarian Geological Society 59, 133-138.
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Ilieva, T. K.
1998
Change of the echinoid fauna across the Cretaceous-Tertiary boundary section in the area of the town Byala, Varna District