Classification
320 - Political science
53
333 - Economics of land & energy
53
630 - Agriculture & related technologies
363 - Other social problems & services
30
330 - Economics
20
380 - Commerce, communications & transportation
8
304 - Factors affecting social behavior
6
610 - Medicine & health
6
600 - Technology
5
370 - Education
2
336 - Public finance
1