THOMSON, James K. Wallstale dun, Polmaise, Stirling. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 101, p. 119–121, 1971. DOI: 10.9750/PSAS.101.119.121. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8748. Acesso em: 8 may. 2024.