Petrie, G. 1865. Notice of a Barrow containing Cists, on the Farm of Newbigging, near Kirkwall: and at Ibister, in the parish of Rendall, Orkney. Proceedings of the Society of Antiquaries of Scotland. 6, (Nov. 1865), 411–418. DOI:https://doi.org/10.9750/PSAS.006.411.418.