DOUGLAS, William. Fast Castle and its Owners : some Notes on their History. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 55, p. 56–83, 1921. DOI: 10.9750/PSAS.055.56.83. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/7504. Acesso em: 4 may. 2024.