Links
Cystoidea - cystoids
P. D. McDermott, C. R. C. Paul: A new Upper Ordovician aristocystitid diploporite genus (Echinodermata) from the Llanddowror district, South Wales
Gutiérrez-Marco J. C., Colmenar J. (2011): Biostratigraphy of the Genus Calix in the Middle Ordovician of the Southern Central Iberian Zone
Ordovician of the World, Instituto Geológico y Minero de España Prokop R. J. (1973): Codiacystis bohemica (Barrande, 1887) from the Ordovician of Libya (Cystoidea)
Časopis pro mineralogii a geologii, 18 (1): 73-74 C.R.C Paul, J.C. Gutiérrez-Marco (2020): Enodicalix (Diploporita, Aristocystitidae): A new echinoderm genus from the Middle Ordovician of Spain
Geologica Acta, 18.3, 1-8 Prokop R. J. (1965): Hippocystis sculptus (Barrande, 1887) in the Bohemian Middle Ordovician (Cystoidea)
Věst. Ústř. Úst. geol., 40, 4, 303-306. Praha Klouček C. (1917): Nová cystidea z d1
Rozpr. Čes. Akad. Věd. Slovesn. Umění, Tř. II, 26, 17, 1-4. Praha Paul C. R. C. (2018): Prokopius, a new name for "Hippocystis sculptus” Prokop, 1965, and the status of the genus Hippocystis Bather, 1919 (Echinodermata; Diploporita)
Bulletin of Geosciences 93(3) , 337–346 Prokop R. J. (1964): Sphaeronitoidea Neumayr of the Lower Paleozoic of Bohemia (Cystoidea, Diploporita)
Sbor. geol. Věd, Paleont., 3, 7-37. Praha T. J. Frest, H. L. Strimple and C. R. C. Paul (2011): The North American Holocystites Fauna (Echinodermata: Blastozoa: Diploporita): Paleobiology and Systematics
Bulletins of American Paleontology 380