Allen, J.R. 1894. Report on the Photographs of the Sculptured Stones earlier than A.D. 1100, in the district of Scotland north of the River Dee, obtained under the Jubilee Gift of His Excellency Dr R. H. Gunning, F.S.A. Scot. Proceedings of the Society of Antiquaries of Scotland. 28, (Nov. 1894), 150–177. DOI:https://doi.org/10.9750/PSAS.028.150.177.