Classification
900 - History & geography
330 - Economics
170
320 - Political science
163
300 - Social sciences
31
576 - Genetics & evolution
30
600 - Technology
17
620 - Engineering & allied operations
16
700 - The arts; fine & decorative arts
15
340 - Law
12
333 - Economics of land & energy
9
363 - Other social problems & services
7
380 - Commerce, communications & transportation
6
000 - Computer science, information & general works
5
630 - Agriculture & related technologies
5
551 - Geology, hydrology & meteorology
4
580 - Plants (Botany)
4
581 - Specific topics in natural history
4
304 - Factors affecting social behavior
2
336 - Public finance
2
540 - Chemistry & allied sciences
2
301 - Sociology & anthropology
1
332 - Financial economics
1
350 - Public administration & military science
1
500 - Natural sciences & mathematics
1
610 - Medicine & health
1
612 - Human physiology
1
657 - Accounting
1
720 - Architecture
1