APA (7th ed.) Citation

Firth, Chisholm, & Doherty. (2006). Astronomy. Usborne.

Chicago Style (17th ed.) Citation

Firth, Chisholm, and Doherty. Astronomy. London: Usborne, 2006.

MLA (8th ed.) Citation

Firth, et al. Astronomy. Usborne, 2006.

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