| Existence of resolvable group divisible designs with block size four I Recent countries visiting this post |  |
 | 6 | United States |
 | 1 | Germany |
 | 1 | |
 | 1 | Russian Federation |
| Existence of resolvable group divisible designs with block size four I Recent countries visiting this post | |
| 6 | United States |
| 1 | Germany |
| 1 | |
| 1 | Russian Federation |