Gordon, R., & Williams, B. J. (2008). Tunnels (1st American ed.). Chicken House/Scholastic.
Lua i Stíl Chicago (17ú heag.)Gordon, Roderick, agus Brian James Williams. Tunnels. 1st American ed. New York: Chicken House/Scholastic, 2008.
Lua MLA (9ú heag.)Gordon, Roderick, agus Brian James Williams. Tunnels. 1st American ed. Chicken House/Scholastic, 2008.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.