Thorpe, R.S.; Leat, P.T.; Mann, A.C.; Howells, M.F.; Reedman, A.J.; Campbell, S.D. G. (1993): «Magmatic evolution of the Ordovician Snowdon Volcanic Centre, North Wales (UK)», Journal of Petrology. 34 (4): 711–741. Bibcode:1993JPet...34..711T. doi:10.1093/petrology/34.4.711.
Reedman, A.J.; Colman, T.B.; Campbell, S.D.G.; Howells, M.F. (1985): «Volcanogenic mineralization related to the Snowdon Volcanic Group (Ordovician), Gwynedd, North Wales», Journal of the Geological Society. 142 (5): 875–888. Bibcode:1985JGSoc.142..875R. doi:10.1144/gsjgs.142.5.0875. S2CID 128875080.
Howe, G. Melvyn (1957): «Weather and climate», Bowen, Emrys G., red.: Wales: A Physical, Historical and Regional Geography. Regional geography series. Methuen. s. 53–94.
Thorpe, R.S.; Leat, P.T.; Mann, A.C.; Howells, M.F.; Reedman, A.J.; Campbell, S.D. G. (1993): «Magmatic evolution of the Ordovician Snowdon Volcanic Centre, North Wales (UK)», Journal of Petrology. 34 (4): 711–741. Bibcode:1993JPet...34..711T. doi:10.1093/petrology/34.4.711.
Reedman, A.J.; Colman, T.B.; Campbell, S.D.G.; Howells, M.F. (1985): «Volcanogenic mineralization related to the Snowdon Volcanic Group (Ordovician), Gwynedd, North Wales», Journal of the Geological Society. 142 (5): 875–888. Bibcode:1985JGSoc.142..875R. doi:10.1144/gsjgs.142.5.0875. S2CID 128875080.
Reedman, A.J.; Colman, T.B.; Campbell, S.D.G.; Howells, M.F. (1985): «Volcanogenic mineralization related to the Snowdon Volcanic Group (Ordovician), Gwynedd, North Wales», Journal of the Geological Society. 142 (5): 875–888. Bibcode:1985JGSoc.142..875R. doi:10.1144/gsjgs.142.5.0875. S2CID 128875080.