Black, G.F. 1895. Notes on a Silver-mounted Charm-Stone of Rock-Crystal from Inverleny, with Notices of other Scottish Balls of Rock-Crystal and of Superstitions connected therewith. Proceedings of the Society of Antiquaries of Scotland. 29, (Nov. 1895), 439–448. DOI:https://doi.org/10.9750/PSAS.029.439.448.