APA (7th ed.) Citation

Heyworth, R. M. B. (2007). Science in focus chemestry `O` Level. Longman.

Chicago Style (17th ed.) Citation

Heyworth, Rex M,JGR Briggs. Science in Focus Chemestry `O` Level. Longman, 2007.

MLA (8th ed.) Citation

Heyworth, Rex M,JGR Briggs. Science in Focus Chemestry `O` Level. Longman, 2007.

Warning: These citations may not always be 100% accurate.