1. The graptolite biostratigraphy of a Llandovery outlier near Llanystumdwy, Gwynedd, North Wales;Baker;Geological Magazine,1981
2. Geochemical discrimination of Silurian mudstones according to depositional process and provenance within the southern Welsh Basin;Ball;Geological Magazine,1992
3. Graptolites de Boheme;Barrande,1850
4. Graptolites, a fossil case-history of evolution from sessile, colonial animals to automobile superindividuals;Bates;Proceedings of the Royal Society of London,1985
5. Biostratigraphic integration of Ordovician graptolite and conodont zones - a regional overview;Bergstrom,1986