Classification
304 - Factors affecting social behavior
19
330 - Economics
19
610 - Medicine & health
19
320 - Political science
14
370 - Education
9
600 - Technology
8
333 - Economics of land & energy
7
363 - Other social problems & services
4
336 - Public finance
2
380 - Commerce, communications & transportation
2
630 - Agriculture & related technologies
1