Ross, Thomas. “Notes on Sculptured Stones With Chariots, in the Neighbourhood of Auchterarder, and in Perth Museum, and of a Sculptured Monument Recently Found Near Camelon, and Now in the National Museum”. Proceedings of the Society of Antiquaries of Scotland, vol. 36, Nov. 1902, pp. 597-10, doi:10.9750/PSAS.036.597.610.