Classification
330 - Economics
38
304 - Factors affecting social behavior
17
610 - Medicine & health
17
333 - Economics of land & energy
15
370 - Education
14
320 - Political science
13
336 - Public finance
7
363 - Other social problems & services
4
380 - Commerce, communications & transportation
3
600 - Technology
2
630 - Agriculture & related technologies
2