Joass, J.M. 1871. Note on the Discovery of Urns set in a Round Hole in the Ground under a Tumulus, and of an Inverted Urn covering Calcined Bones at Gordonbush, Sutherlandshire. In a Letter to John Stuart, LL.D., Secretary. Proceedings of the Society of Antiquaries of Scotland. 8, (Nov. 1871), 466. DOI:https://doi.org/10.9750/PSAS.008.466.