Christison, David. “Account of the Excavation of the Camps and Earthworks at Birrenswark Hill in Annandale, Undertaken by the Society in 1898: (I) General History of the Place”. Proceedings of the Society of Antiquaries of Scotland, vol. 33, Nov. 1899, pp. 198-1, doi:10.9750/PSAS.033.198.218.