MIKULÁŠ, R. Trace fossils and bioturbation in the lower part of the Šárka Formation at Praha - Červený vrch Hill (Ordovician, Barrandian area, Czech Republic). Bulletin of Geosciences. 2003, 78(2), 141-146. ISSN 1214-1119. E-ISSN 1802-8225. Dostupné z: http://www.geology.cz/bulletin/contents/2003/vol78no2/a08-mikulas.pdf