Allen, J.R.; Anderson, J. (1903), Early Christian Monuments of Scotland, Edinburgh: The Society of Antiquaries of Scotland. Volumes 1 and 2; Volume 3.
discovery.com
news.discovery.com
Viegas, J. (31 de marzo de 2010). «New Written Language of Ancient Scotland Discovered». Discovery.com. Archivado desde el original el 20 de mayo de 2011. Consultado el 11 de octubre de 2022. «Once thought to be rock art, carved depictions of soldiers, horses and other figures are in fact part of a written language dating back to the Iron Age. A new written language, belonging to the early Pict society of Scotland, has just been identified».
fanad.net
Griffen, Toby D. (March 2000). «The Pictish Art of the Archer Guardian». fanad.net/grifpub.html. St Louis, Missouri: Celtic Studies Association of North America. Consultado el 30 de mayo de 2011.
Griffen, Toby D. «The Grammar of the Pictish Symbol Stones». fanad.net/grifpub.html. St Louis, Missouri: Celtic Studies Association of North America. Consultado el 30 de mayo de 2011.
Viegas, J. (31 de marzo de 2010). «New Written Language of Ancient Scotland Discovered». Discovery.com. Archivado desde el original el 20 de mayo de 2011. Consultado el 11 de octubre de 2022. «Once thought to be rock art, carved depictions of soldiers, horses and other figures are in fact part of a written language dating back to the Iron Age. A new written language, belonging to the early Pict society of Scotland, has just been identified».