Edwards, A.J.H. and Bryce, T.H. 1927. Excavation of Graves at Ackergill and of an Earth-house at Freswick Links, Caithness, and a Description of the Discovery of a Viking Grave at Reay, Caithness: With a Preliminary Note on the Skeletal Remains from the Various Graves. Proceedings of the Society of Antiquaries of Scotland. 61, (Nov. 1927), 196–209. DOI:https://doi.org/10.9750/PSAS.061.196.209.