HEWISON, James K. On the Prehitoric forts of the Island of Bute. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 27, p. 281–293, 1893. DOI: 10.9750/PSAS.027.281.293. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/6519. Acesso em: 2 may. 2024.