Macmillan, Hugh. “Notice of Two Boulders Having Rain-Filled Cavities on the Shores of Loch Tay, Formerly Associated With the Cure of Disease”. Proceedings of the Society of Antiquaries of Scotland 18 (November 30, 1884): 369–376. Accessed April 20, 2024. https://journals.socantscot.org/index.php/psas/article/view/6115.