KINGHORN, George. Notes on the Discovery of a Deposit of Polished Stone Axes and Oval Knives of Porphyry, &c., at Modesty, near Bridge of Walls, Shetland. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 29, p. 48–54, 1895. DOI: 10.9750/PSAS.029.48.54. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/6575. Acesso em: 5 may. 2024.