protective cover: 32 phrases in 15 subjects |
Advertising | 1 |
Agrochemistry | 1 |
Astronautics | 4 |
Construction | 3 |
Dentistry | 5 |
Ecology | 1 |
Electronics | 1 |
Energy industry | 1 |
Geology | 1 |
Military | 5 |
Mining | 1 |
Missiles | 1 |
Natural resourses and wildlife conservation | 1 |
Technology | 5 |
Weapons of mass destruction | 1 |