ΕπικεφαλίδαEtheridge, Robert χρησιμοποιείται σε: Bibliothèque nationale de France, Paris
Πηγές
Βρίσκεται σεFossils of the British Islands, stratigraphically and zoologically arranged. Vol. I. Palaeozoic, comprising the Cambrian, Silurian, Devonian, Carboniferous and Permian species, with supplementary appendix brought down to the end of 1886 / by Robert Etheridge, 1888. — Encycl. Britannica. — BN Cat. gén. : Etheridge, Robert (senior)