Cita APA (7a ed.)

Harland, W. B. (1989). A geologic time scale 1989. Cambridge University Press.

Cita Chicago Style (17a ed.)

Harland, Walter Brian. A Geologic Time Scale 1989. New York: Cambridge University Press, 1989.

Cita MLA (9a ed.)

Harland, Walter Brian. A Geologic Time Scale 1989. Cambridge University Press, 1989.