1. Notes on the Speeton ammonites;Danford;Proc. Yorks, geol. Soc.,1906
2. A new hetermorph ammonite from the Lower Cretaceous of Yorkshire;Doyle;Palaeontology,1963
3. A lithological subdivision of the Speeton Clay C Beds (Hauterivian), East Yorkshire;Fletcher;Proc. Yorks, geol. Soc.,1969
4. Ammonites of Early Cretaceous age (Valanginian and Hauterivian) from the Pacific Coast States;Imlay;Prof. Pap. U.S. geol. Surv.,1960
5. Ammonites of Tethylan ancestry in the early Lower Cretaceous of north-west Europe;Kemper;Palaeontology,1981