PETRIE, George. Notice of the Brochs or Large Round Towers of Orkney, with Plans, Sections, and Drawings, and Tables of Measurements of Orkney and Shetland Brochs. Archaeologia Scotica, [S. l.], v. 5, p. 71–94, 1891. Disponível em: https://journals.socantscot.org/index.php/arch-scot/article/view/313. Acesso em: 2 may. 2024.