TRAILL, William; KIRKNESS, William. Hower, a prehistoric structure on Papa Westray, Orkney. Proceedings of the Society of Antiquaries of Scotland, [S. l.], v. 71, p. 309–321, 1937. DOI: 10.9750/PSAS.071.309.321. Disponível em: https://journals.socantscot.org/index.php/psas/article/view/8050. Acesso em: 27 apr. 2024.