| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| It is easy to understand one by one in English 2. - New course of study support ISBN: 4053029082 | 978-4-05-302908-9 (4-05-302908-2) | 2009 |
| It is easy to understand one by one in English 3. ISBN: 4053031133 | 978-4-05-303113-6 (4-05-303113-3) | 2010 |
| It is easy to understand one by one tertiary Eiken.: Listening with CD ISBN: 4053039193 | 978-4-05-303919-4 (4-05-303919-3) | 2013 |