Stewart, W Balfour, and W Boyd Dawkins. 1914. “Notes on a Further Excavation of Ancient Dwellings at Skara, in the Parish of Sandwick, Orkney, Made During August 1913: With Notes on the Remains Found”. Proceedings of the Society of Antiquaries of Scotland 48 (November):344-55. https://doi.org/10.9750/PSAS.048.344.355.