APA Style

Keene, C. (2015). Nancy's Mysterious Letter (Nancy Drew #8) . New York, USA: Grosset & Dunlap (Penguin Young Readers Group).

MLA Style

Keene, Carolyn. "Nancy's Mysterious Letter (Nancy Drew #8)". New York, USA: Grosset & Dunlap (Penguin Young Readers Group), 2015. Printed Book.