^Henderson, Jon C. The Atlantic Iron Age: Settlement and Identity in the First Millennium BC. Routledge. 2007: 292–295.
^Sims-Williams, Patrick. Studies on Celtic Languages before the Year 1000. CMCS. 2007: 1.
^Koch, John. Celtic Culture: A Historical Encyclopedia. ABC-CLIO. 2006: 1455.
^Eska, Joseph. Continental Celtic. Roger Woodard (编). The Ancient Languages of Europe. Cambridge. 2008.
^Forsyth, Katherine. John Koch , 编. Celtic Culture: A Historical Encyclopedia. ABC-CLIO. 2006: 1444, 1447.
^Forsyth, Katherine, Language in Pictland : the case against "non-Indo-European Pictish" (Utrecht: de Keltische Draak, 1997), 27.
^Jackson, Kenneth. The Pictish Language. F. T. Wainwright (编). The Problem of the Picts. Edinburgh: Nelson. 1955: 129–166.
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