Classification
600 - Technology
11
610 - Medicine & health
11
900 - History & geography
11
100 - Philosophy & psychology
2
300 - Social sciences
2
170 - Ethics
1
333 - Economics of land & energy
1
363 - Other social problems & services
1
370 - Education
1
500 - Natural sciences & mathematics
1
530 - Physics
1
620 - Engineering & allied operations
1