Cup-marked Stones in Strathtay, Perthshire. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 56, p. 34–43, 1922. DOI: 10.9750/PSAS.056.34.43. Disponível em: https://soas-test.journals.ed.ac.uk/index.php/psas/article/view/7527. Acesso em: 27 oct. 2025.