Classification
630 - Agriculture & related technologies
363 - Other social problems & services
192
333 - Economics of land & energy
120
330 - Economics
110
380 - Commerce, communications & transportation
84
320 - Political science
78
600 - Technology
39
304 - Factors affecting social behavior
33
610 - Medicine & health
33
370 - Education
10
336 - Public finance
7
340 - Law
2