Ritchie, J. N. G., Marwick, E. W., Henshall, A. S., Savory, L., Clutton-Brock, J., Caseldine, C. J., … Marwick, E. W. (1978). The Stones of Stenness, Orkney: With an account of the Stone of Odin. Proceedings of the Society of Antiquaries of Scotland, 107, 1–60. https://doi.org/10.9750/PSAS.107.1.60