SIMPSON, W Douglas. Cairnbulg Castle, Aberdeenshire. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 83, p. 32–44, 1951. DOI: 10.9750/PSAS.083.32.44. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8330. Acesso em: 4 may. 2024.