17 of them.
- Important discrete mathematical group | 0, 425, 18
- Important mathematical group | 0, 425, 19
- Group | 0, 5k, 90
- Algebra | 0, 8k, 180
- Mathematics | 17, 30k, 679
- Ciro Santilli's Homepage | 262, 222k, 4k
- Classification | 107
- The beauty of mathematics | 405, 846, 8