Gray, D. E. (1966). Man and his physical world. D. Van Nostrand.
Chicago Style (17th ed.) ZitazioaGray, Dwight E. Man and His Physical World. Princeton: D. Van Nostrand, 1966.
MLA (9th ed.) ZitazioaGray, Dwight E. Man and His Physical World. D. Van Nostrand, 1966.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.