| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 2016 | 978-0-9965781-1-0 | Lynette M. Smith | How to Write a Heartfelt Letter of Appreciation to a Product Creator or Service Provider (Volume 3) |
| '' | 978-0-9965781-3-4 | '' | How to Write a Heartfelt Letter of Appreciation to a Supervisor or Employee (Volume 4) |