MUNRO, Robert. Notes on Ornamental Stone Balls, with reference to two Specimens presented to the National Museum by Mr Andrew Urquhart. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 41, p. 290–300, 1907. DOI: 10.9750/PSAS.041.290.300. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/7087. Acesso em: 4 may. 2024.