Smith, John Alexander. “Notes of Rock Sculpturings of Cups and Concentric Rings, and ’The Witch’s Stone’ on Tormain Hill; Also of Some Early Remains on the Kaimes Hill, &C., Near Ratho, Edinburghshire”. Proceedings of the Society of Antiquaries of Scotland, vol. 10, Nov. 1874, pp. 141-5, doi:10.9750/PSAS.010.141.151.