MARSHALL, Dorothy N. Further notes on carved stone balls. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 113, p. 628–630, 1984. DOI: 10.9750/PSAS.113.628.630. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/9140. Acesso em: 19 apr. 2024.