Classification
100 - Philosophy & psychology
330 - Economics
333 - Economics of land & energy
3
363 - Other social problems & services
581 - Specific topics in natural history
3
900 - History & geography
300 - Social sciences
2
320 - Political science
2
576 - Genetics & evolution
2
170 - Ethics
1
301 - Sociology & anthropology
1
350 - Public administration & military science
1
600 - Technology
1
610 - Medicine & health
1