| A prior-free revenue maximizing auction for secondary spectrum access Recent countries visiting this post |  |
 | 5 | United States |
 | 3 | |
 | 1 | Italy |
 | 1 | Germany |
| A prior-free revenue maximizing auction for secondary spectrum access Recent countries visiting this post | |
| 5 | United States |
| 3 | |
| 1 | Italy |
| 1 | Germany |