Classification
380 - Commerce, communications & transportation
330 - Economics
267
363 - Other social problems & services
210
333 - Economics of land & energy
179
320 - Political science
153
630 - Agriculture & related technologies
84
336 - Public finance
59
600 - Technology
58
304 - Factors affecting social behavior
53
610 - Medicine & health
53
370 - Education
10
340 - Law
2