Não informado. (1969). Tunnels and Tunnelling. Morgan Grampian.
Lua i Stíl Chicago (17ú heag.)Não informado. Tunnels and Tunnelling. London: Morgan Grampian, 1969.
Lua MLA (8ú heag.)Não informado. Tunnels and Tunnelling. Morgan Grampian, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.