| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| NTT頭脳集団の野望 NTTzunoushuudannoyabou | 978-4-06-203150-9 (4-06-203150-7) | 1987 |
| ザ・電話戦争―新電電VS.第二電電 za・denwasensou―ara/ | 978-4-06-201860-9 (4-06-201860-8) | 1985 |
| 自分を活かす転職の研究 jibunwoikasutenshokunokenkyuu | 978-4-06-204417-2 (4-06-204417-X) | 1989 |