APA (7th ed.) Citation

Bok, B. J., Messel, H., & Butler, S. T. (1977). Focus on the stars. Heinemann Educational.

Chicago Style (17th ed.) Citation

Bok, Bart J., H. Messel, and S. T. Butler. Focus on the Stars. London: Heinemann Educational, 1977.

MLA (9th ed.) Citation

Bok, Bart J., et al. Focus on the Stars. Heinemann Educational, 1977.