APA (7th ed.) Citation

Hawking, S., Hawking, L., & Bielecki, J. (2021). Unlocking the universe. Puffin.

Chicago Style (17th ed.) Citation

Hawking, Stephen, Lucy Hawking, and Jan Bielecki. Unlocking the Universe. London: Puffin, 2021.

MLA (9th ed.) Citation

Hawking, Stephen, et al. Unlocking the Universe. Puffin, 2021.