APA (7th ed.) Citation

Humberstone, E., Ashman, I., & Simpson, S. (1981). Finding out about things at home. Usborne.

Chicago Style (17th ed.) Citation

Humberstone, Eliot, Ian Ashman, and Sarah Simpson. Finding Out About Things at Home. London: Usborne, 1981.

MLA (9th ed.) Citation

Humberstone, Eliot, et al. Finding Out About Things at Home. Usborne, 1981.