GORDON, G.; MITCHELL, A. 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, v. 12, p. 202-206, 30 nov. 1877.