Allen, John Romilly. 1891. “Report on the Sculptured Stones Older Than A.D. 1100, With Symbols and Celtic Ornament, in the District of Scotland, North of the River Dee; Obtained under the Victoria Jubilee Gift of His Excellency Dr. R. H. Gunning, F.S.A. Scot”. Proceedings of the Society of Antiquaries of Scotland 25 (November):422-31. https://doi.org/10.9750/PSAS.025.422.431.