A catalogue of a collection of plaques, medallions, vases, figures, etc., in coloured jasper and basalt, produced by Josiah Wedgwood, F.R.S., at Etruria, in the county of Stafford, England, 1760-1795,

Mode of access: Internet.

Die Basalt-Gebilde in ihren Beziehungen zu normalen und abnormen Felsmassen,

Mode of access: Internet.