| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Speak German in 90 Days: A Self Study Guide to Becoming Fluent | 978-1-5175-1944-5 (1-5175-1944-6) | 2015 |
| Speak German Now!: The Go-To Guide for Essential German Basics | 978-1-5177-8480-5 (1-5177-8480-8) | 2015 |
| Speak Japanese in 90 Days: A Self Study Guide to Becoming Fluent | 978-1-5186-9971-9 (1-5186-9971-5) | 2015 |