J. Anderson, “Notice of a Fragment of a Silver Penannular Brooch, ornamented with Gold Filigree Work and Amber Settings, found at Achavrole, Dunbeath, Caithness, in 1860: and of two Silver Brooches, the property of Andrew Heiton, F.S.A. Scot., said to have been found in the neighbourhood of Perth”, PSAS, vol. 14, pp. 445–452, Nov. 1880.