Coles, Frederick R. “Report on the Stone Circles of North-Eastern Scotland, Chiefly in Auchterless and Forgue, With Measured Plans and Drawings, Obtained under the Gunning Fellowship”. Proceedings of the Society of Antiquaries of Scotland, vol. 37, Nov. 1903, pp. 82-142, doi:10.9750/PSAS.037.82.142.