MITCHELL, Arthur. Notice of Buildings designed for Defence on an Island in a Loch at Hogsetter, in Whalsay, Shetland. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 15, p. 303–315, 1881. DOI: 10.9750/PSAS.015.303.315. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/5978. Acesso em: 3 may. 2024.