Classification
600 - Technology
320 - Political science
18
330 - Economics
10
333 - Economics of land & energy
9
620 - Engineering & allied operations
7
363 - Other social problems & services
6
300 - Social sciences
4
551 - Geology, hydrology & meteorology
4
900 - History & geography
4
140 - Specific philosophical schools
3
304 - Factors affecting social behavior
3
340 - Law
3
370 - Education
3
630 - Agriculture & related technologies
3
170 - Ethics
2
380 - Commerce, communications & transportation
2
581 - Specific topics in natural history
2
700 - The arts; fine & decorative arts
2
100 - Philosophy & psychology
1
301 - Sociology & anthropology
1
500 - Natural sciences & mathematics
1
540 - Chemistry & allied sciences
1
610 - Medicine & health
1