Smith, John Alexander. “Notice of the Remains of the Great Auk, or Gare-Fowl (Alca Impennis, Linn.), Found in Caithness; With Notes of Its Occurrence in Scotland and of Its Early History”. Proceedings of the Society of Antiquaries of Scotland, vol. 13, Nov. 1879, pp. 76-105, doi:10.9750/PSAS.013.76.105.