Anderson, J. 1891. Notice of the Excavation of the Brochs of Yarhouse, Brounaben, Bowermadden, Old Stirkoke, and Dunbeath, in Caithness, with Remarks on the Period of the Brochs; and an Aplpendix, containing a Collected List of the Brochs of Scotland, and Early Notices of many of them.and an appendix containing a collected list of the brochs of Scotland, and early notices of many of them. Archaeologia Scotica. 5, (Nov. 1891), 131–198.