Gordon, G. and Mitchell, A. (1877) “Notice of Incised Sculpturings on the Steatite Rock at Feideland, the Extreme North of the Mainland of Shetland, and of a Cluster of Ruined Structures Styled Picts’ Houses, on the Kaim of Isbister, Shetland.”, Proceedings of the Society of Antiquaries of Scotland, 12, pp. 202-206. doi: 10.9750/PSAS.012.202.206.