“Letter from Thomas Robertson, Esq., to the Earl of Buchan, respecting the Discovery of a Stone Coffin at Arbroath, supposed to contain the Remains of King William the Lyon”, arch-scot, vol. 3, pp. 297–298, Nov. 1832, Accessed: Dec. 11, 2025. [Online]. Available: https://journals.socantscot.org/index.php/arch-scot/article/view/240