| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| 21 Easy Ukulele Songs For Christmas | 978-1-5186-8155-4 (1-5186-8155-7) | 2015 | Jenny Peters |
| 21 Songs in 6 Days: Learn Ukulele the Easy Way: Book + online video | 978-1-5027-6027-2 (1-5027-6027-4) | 2014 | " |