GRANT, Walter G. An earth-house at Gripps, Frotoft, Rousay, Orkney. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 73, p. 273–275, 1939. DOI: 10.9750/PSAS.073.273.275. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8112. Acesso em: 24 apr. 2024.