Richardson, J. S. (1907) “Notice of Kitchen-midden Deposits on North Berwick Law, and other Antiquities in the vicinity of North Berwick; with a Note of an Undescribed Sculptured Stone, with Symbols, in the Island of Raasay”, Proceedings of the Society of Antiquaries of Scotland, 41, pp. 424–436. doi: 10.9750/PSAS.041.424.436.