Smith, J.A. 1880. Additional Notes to Notice of the Remains of the Great Auk (Alca impennis, Linn.), found in Caithness; with Notes of its Occurrence, &c., in Scotland, and of its Early History. Proceedings of the Society of Antiquaries of Scotland. 14, (Nov. 1880), 436–444. DOI:https://doi.org/10.9750/PSAS.014.436.444.