Clarke, H., & Lapper, i. I. (1983). <Os >vikings. Verbo.
Lua i Stíl Chicago (17ú heag.)Clarke, Helen, agus il. Ivan Lapper. <Os >vikings. Verbo, 1983.
Lua MLA (8ú heag.)Clarke, Helen, agus il. Ivan Lapper. <Os >vikings. Verbo, 1983.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.