Jovčeva, P. M. (1987). The genus Schackoina (Foraminifera) from the Upper Albian and Lower Cenomanian in Central North Bulgaria (in Russian with English abs.). Paleontology, Stratigraphy and Lithology, Bulgarian Academy of Sciences. 24: 87-96.
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Jovčeva, P. M.
1987
The genus Schackoina (Foraminifera) from the Upper Albian and Lower Cenomanian in Central North Bulgaria (in Russian with English abs.)
Paleontology, Stratigraphy and Lithology, Bulgarian Academy of Sciences