Callander, J.G. and Grant, W.G. 1936. A stalled chambered cairn, the Knowe of Ramsay, at Hullion, Rousay, Orkney. Proceedings of the Society of Antiquaries of Scotland. 70, (Nov. 1936), 407–419. DOI:https://doi.org/10.9750/PSAS.070.407.419.