APA (7th ed.) Citation

Crawshaw, B. H., & Ritchie, J. H. (1979). "O" grade questions in physics. Heinemann Educational.

Chicago Style (17th ed.) Citation

Crawshaw, B. H., and J. H. Ritchie. "O" Grade Questions in Physics. London: Heinemann Educational, 1979.

MLA (9th ed.) Citation

Crawshaw, B. H., and J. H. Ritchie. "O" Grade Questions in Physics. Heinemann Educational, 1979.