RCAHMS records the monument as HY 42 NW 4.
Ashmore, P. (1995) The ancient monuments of Orkney. HMSO; Edinburgh.
Cross, M. (1994) Bibliography of Monuments in the Care of the Secretary of State for Scotland, 601-2, Glasgow, 1994.
RCAHMS (1946) Twelfth Report with an Inventory of the Ancient Monuments of Orkney and Shetland, vol. II, Inventory of Orkney. HMSO; Edinburgh.