| On Approximating Four Covering and Packing Problems Recent countries visiting this post |  |
 | 4 | United States |
 | 1 | Sweden |
 | 1 | |
 | 1 | China |
 | 1 | Turkey |
 | 1 | Russian Federation |
| On Approximating Four Covering and Packing Problems Recent countries visiting this post | |
| 4 | United States |
| 1 | Sweden |
| 1 | |
| 1 | China |
| 1 | Turkey |
| 1 | Russian Federation |