| Verfasser | Häufigkeit |
| Koopmann, Helmut 1933- |
16 |
| Jonas, Klaus W. 1920-2016 |
8 |
| Borges, Malte |
6 |
| Koopmann, Jutta |
6 |
| Koopmann, Jörg 1968- |
6 |
| Elser, Eike |
4 |
| Koopmann, Jens |
3 |
| Koopmann, Johann Karl Heinrich 1797-1894 |
3 |
| Akdemir, Nevra 1977- |
2 |
| Elle, Johanna |
2 |
| Grittmann, Elke 1966- |
2 |
| Koopmann, Hans-Jürgen |
2 |
| Koopmann, Johann |
2 |
| Koopmann, Ulrike 1971- |
2 |
| Michel, Reiner 1939- |
2 |
| Müller, Carsten |
2 |
| Müller, Daniela |
2 |
| Schmoll, Josef A. 1915-2010 |
2 |
| Schwenken, Helen 1972- |
2 |
| Ullmann, Johanna |
2 |