Classification
363 - Other social problems & services
33
320 - Political science
13
330 - Economics
7
900 - History & geography
6
140 - Specific philosophical schools
5
300 - Social sciences
5
581 - Specific topics in natural history
5
700 - The arts; fine & decorative arts
5
100 - Philosophy & psychology
4
333 - Economics of land & energy
3
551 - Geology, hydrology & meteorology
3
720 - Architecture
2
800 - Literature & rhetoric
2
200 - Religion
1
338 - Production
1
370 - Education
1
400 - Language
1
410 - Linguistics
1
553 - Economic geology
1
630 - Agriculture & related technologies
1