Gray E. Elizabeth. (1999). Jorney to the Centre of the Earth. Swansea, Express Publishing, 1999.
Lua i Stíl Chicago (17ú heag.)Gray E. Elizabeth. Jorney to the Centre of the Earth. Swansea, Express Publishing, 1999, 1999.
Lua MLA (9ú heag.)Gray E. Elizabeth. Jorney to the Centre of the Earth. Swansea, Express Publishing, 1999, 1999.
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