Taxon - Odkazy a literatura
Havlíček V., Vaněk J. (1966): The Biostratigraphy of the Ordovician of Bohemia, Sborník geologických věd, Paleontologie, 8 [jako Orthoceras importunum Barr.]
Marek J. (1999): Ordovician cephalopods of the Prague Basin (Barrandian area, Czech Republic): a review, Acta universitatis Carolinae - Geologica, 43 (1/2), 413-416 [jako Orthoceras importunum]