| Verfasser | Häufigkeit |
|---|---|
| Zweifel, Richard G. 1926-2019 | 14 |
| Gallay, R. | 3 |
| Zweifel, J. | 3 |
| Cogger, Harold G. 1935- | 2 |
| Burton, Thomas C. | 1 |
| Corbaz, R. | 1 |
| Duellman, William E. 1930- | 1 |
| Keller, C. | 1 |
| Kirshner, David | 1 |
| Menzies, James I. | 1 |
| Price, David | 1 |
| Richards, Stephen J. | 1 |