The Mona Mousa code /
Geronimo Stilton ; illustrations by Matt Wolf.
- New York : Scholastic, [2005]
- 112 p. : col. ill., col. maps ; 20 cm.
- Geronimo Stilton ; 15 .
"#15"--Spine. Translation of: Il sorriso di Monna Topisa.
Geronimo investigates to see if the famous painting Mona Mousa holds a secret code.