Calder, Charles S T, and A J H Edwards. “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: Including Report on the Pottery”. Proceedings of the Society of Antiquaries of Scotland 72 (November 30, 1938): 193–213. Accessed April 12, 2024. https://journals.socantscot.org/index.php/psas/article/view/8068.