SIMPSON, W Douglas. Tolquhon Castle and its Builder. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 72, p. 248–272, 1938. DOI: 10.9750/PSAS.072.248.272. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8076. Acesso em: 5 may. 2024.