APA (7th ed.) Citation

Novak, K., & Grubb, J. The finder's stone trilogy. Penguin Books.

Chicago Style (17th ed.) Citation

Novak, Kate, and Jeff Grubb. The Finder's Stone Trilogy. London u.a: Penguin Books.

MLA (9th ed.) Citation

Novak, Kate, and Jeff Grubb. The Finder's Stone Trilogy. Penguin Books.

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