APA (7th ed.) Citation

Harland, W. B. (1990). A geologic time scale 1989. C.U.Pr..

Chicago Style (17th ed.) Citation

Harland, W. Brian. A Geologic Time Scale 1989. Cambridge: C.U.Pr., 1990.

MLA (9th ed.) Citation

Harland, W. Brian. A Geologic Time Scale 1989. C.U.Pr., 1990.