H-Bar Enterprises · Trend Factor Press
| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Negative Nine | 978-0-7639-0719-8 (0-7639-0719-7) | 2008 | Amy K. C. S. Vanderbilt Ph.D. |
| Negative Nine: The Early Math Series (Book 1) | 978-0-9818669-1-8 (0-9818669-1-3) | 2008 | " |
| Zero, Zero Everywhere!: The Early Math Series | 978-0-9818669-2-5 (0-9818669-2-1) | 2008 | " |