RITCHIE, Graham; WATKINS, Trevor. Stuart Piggott. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 126, p. xiii-xviii, 1997. DOI: 10.9750/PSAS.126.xiii.xviii. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/10408. Acesso em: 2 may. 2024.