system concept: 44 phrases in 15 subjects |
American usage, not spelling | 1 |
Astronautics | 4 |
Automated equipment | 3 |
Aviation | 3 |
Computer networks | 2 |
Diplomacy | 1 |
Education | 1 |
Mathematics | 1 |
Military | 18 |
Power system protection | 1 |
Programming | 5 |
Seismology | 1 |
Surveying | 1 |
Telecommunications | 1 |
Weapons of mass destruction | 1 |