Joass, J. (1872) “Notice of the Excavation of the Pictish Towers at Cinntrolla, Carnliath, and Craig-Carril in Sutherland, with Notes on Neighbouring Brochs; and an appended Report by T. Aitken, M.D., F.A.S.L., Inverness, on the Crania found in and about them”, Proceedings of the Society of Antiquaries of Scotland, 9, p. 60. doi: 10.9750/PSAS.009.60.1.