APA Style

Stilton, G., Cernuschi, C. (2008). Geronimo Stilton valley of the giant skeletons . New York, USA: Scholastic Inc.

MLA Style

Stilton, Geronimo., Cernuschi, Claudio. "Geronimo Stilton valley of the giant skeletons". New York, USA: Scholastic Inc, 2008. Text.