WATSON, W J. The Circular Forts of North Perthshire. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 47, p. 30–60, 1913. DOI: 10.9750/PSAS.047.30.60. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/7285. Acesso em: 19 apr. 2024.