Classification
630 - Agriculture & related technologies
363 - Other social problems & services
137
333 - Economics of land & energy
84
330 - Economics
78
380 - Commerce, communications & transportation
57
320 - Political science
50
600 - Technology
31
304 - Factors affecting social behavior
23
610 - Medicine & health
23
336 - Public finance
6
370 - Education
6
340 - Law
1