Classification
363 - Other social problems & services
20
600 - Technology
620 - Engineering & allied operations
17
581 - Specific topics in natural history
15
333 - Economics of land & energy
13
330 - Economics
8
551 - Geology, hydrology & meteorology
6
320 - Political science
5
700 - The arts; fine & decorative arts
5
900 - History & geography
5
630 - Agriculture & related technologies
4
300 - Social sciences
1
340 - Law
1
350 - Public administration & military science
1
370 - Education
1
400 - Language
1
540 - Chemistry & allied sciences
1