| 513120 |
Scholastic magazine and periodical publishers, exclusively on Internet |
| 513120 |
Scientific journal and periodical publishers |
| 513120 |
Scientific journal and periodical publishers (except exclusive Internet publishing) |
| 513120 |
Scientific journal and periodical publishers and printing combined |
| 513120 |
Scientific journal and periodical publishers, exclusively on Internet |
| 513120 |
Technical magazine and periodical publishers |
| 513120 |
Technical magazine and periodical publishers (except exclusive Internet publishing) |
| 513120 |
Technical magazine and periodical publishers and printing combined |
| 513120 |
Technical magazine and periodical publishers, exclusively on Internet |
| 513120 |
Television guide publishers |