| Deutsch | deu-000 |
| Martin Seligman | |
| dansk | dan-000 | Martin Seligman |
| English | eng-000 | Martin Seligman |
| italiano | ita-000 | Martin E. P. Seligman |
| Nederlands | nld-000 | Martin Seligman |
| bokmål | nob-000 | Martin Seligman |
| español | spa-000 | Martin Seligman |
| svenska | swe-000 | Martin Seligman |