APA (7th ed.) Citation

Harland, W. B., Smith, A. G., & British Petroleum Company. (1990). A Geologic time scale 1989. Cambridge University Press.

Chicago Style (17th ed.) Citation

Harland, W. B., A. Gilbert Smith, and British Petroleum Company. A Geologic Time Scale 1989. Cambridge [England] ; New York, NY: Cambridge University Press, 1990.

MLA (8th ed.) Citation

Harland, W. B., et al. A Geologic Time Scale 1989. Cambridge University Press, 1990.