| Verfasser | Häufigkeit |
|---|---|
| ACKERMAN, JAMES L. | 7 |
| Baer, Melvyn J. | 7 |
| Bosma, James F. | 7 |
| Bosma, A. H. | 2 |
| Armleder, John M. 1948- | 1 |
| Ax, Jan | 1 |
| Bosma, Koos 1952-2015 | 1 |
| Bosma, Marja | 1 |
| Bosma, Yvonne | 1 |
| Buitink, W. J. | 1 |
| Cappon, A. | 1 |
| Klarenbeek, J. V. | 1 |
| Mekking, Aart J. J. | 1 |
| Wieringen, Alphonsus M. L. van 1946- | 1 |