Guttmann, E B A, S J Dockrill, and I A Simpson. “Arable Agriculture in Prehistory: New Evidence from Soils in the Northern Isles”. Proceedings of the Society of Antiquaries of Scotland 134 (November 30, 2005): 53–64. Accessed April 20, 2024. https://journals.socantscot.org/index.php/psas/article/view/9599.