Cengage Learning · Wadsworth; Brooks/Cole
| title | ISBN-13 | year of publication |
|---|---|---|
| Aie W DVD Welten | 978-0-495-91268-2 | 2015 |
| Aud CD Welten Tstng Intro Germ | 978-1-305-50257-4 | 2015 |
| Powerlecture Irc Welten 1e | 978-0-495-91210-1 | 2015 |
| Sam Welten | 978-0-495-91202-6 | 2015 |