CALDER, Charles S T. Notice of Two Standing Stones (one with Pictish Symbols) on the Lands of Peterhead Farm, near Gleneagles, Perthshire. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 81, p. 1–7, 1949. DOI: 10.9750/PSAS.081.1.7. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8270. Acesso em: 5 may. 2024.