| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Dekiru otona no mono no iikata. | 978-4-413-00901-0 (4-413-00901-0) | 2007 |
| Koredake wa shitteokitai otona no kokugoryoku. | 978-4-413-00875-4 (4-413-00875-8) | 2007 |
| Rikei no hanashi ga omoshiroihodo wakaru. | 978-4-413-00802-0 (4-413-00802-2) | 2005 |