A. J. H. Edwards and T. H. Bryce, “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”, PSAS, vol. 61, pp. 196–209, Nov. 1927.