DIXON, D. Encyclopedia Of Science: The Earth Our Planet Its Land, Sea, and Air. Macmillan Publishing Company.
Chicago-viite (17. p.)DIXON, Dougal. Encyclopedia Of Science: The Earth Our Planet Its Land, Sea, and Air. Macmillan Publishing Company.
MLA-viite (8. p.)DIXON, Dougal. Encyclopedia Of Science: The Earth Our Planet Its Land, Sea, and Air. Macmillan Publishing Company.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.