APA
The Mitchell Beazley Joy of Knowledge, . (1976). The physical earth. Londan: Mitchell Beazley Encyclopaeedias.
Chicago
The Mitchell Beazley Joy of Knowledge, . 1976. The physical earth. Londan: Mitchell Beazley Encyclopaeedias.
Harvard
The Mitchell Beazley Joy of Knowledge, . (1976). The physical earth. Londan: Mitchell Beazley Encyclopaeedias.
MLA
The Mitchell Beazley Joy of Knowledge, . The physical earth. Londan: Mitchell Beazley Encyclopaeedias. 1976.
