Calder, C. and Edwards, A. (1938) “Excavations of Three Neolithic Chambered Cairns – One with an Upper and a Lower Chamber – in the Islands of Eday and the Calf of Eday in Orkney”, Proceedings of the Society of Antiquaries of Scotland, 72, pp. 193-213. doi: 10.9750/PSAS.072.193.213.