APA (7th ed.) Citation

Graham, D., Graham, C., & Whitcombe, A. (1998). A level mathematics. Letts Educational.

Chicago Style (17th ed.) Citation

Graham, Duncan, Christine Graham, and Allan Whitcombe. A Level Mathematics. London, UK: Letts Educational, 1998.

MLA (9th ed.) Citation

Graham, Duncan, et al. A Level Mathematics. Letts Educational, 1998.