APA Style

Stilton, G., Marrese, C. (2008). Geronimo Stilton Geronimo and the gold medal mystery . New York, USA: Scholastic Inc.

MLA Style

Stilton, Geronimo., Marrese, Cinzia. "Geronimo Stilton Geronimo and the gold medal mystery". New York, USA: Scholastic Inc, 2008. Text.