Classification
720 - Architecture
25
700 - The arts; fine & decorative arts
11
363 - Other social problems & services
8
320 - Political science
7
900 - History & geography
5
140 - Specific philosophical schools
4
333 - Economics of land & energy
4
300 - Social sciences
3
301 - Sociology & anthropology
2
330 - Economics
2
340 - Law
2
380 - Commerce, communications & transportation
2
551 - Geology, hydrology & meteorology
2
581 - Specific topics in natural history
2
600 - Technology
2
610 - Medicine & health
2
620 - Engineering & allied operations
2
576 - Genetics & evolution
1
630 - Agriculture & related technologies
1