Classification
630 - Agriculture & related technologies
397
363 - Other social problems & services
117
333 - Economics of land & energy
80
330 - Economics
76
320 - Political science
57
380 - Commerce, communications & transportation
43
600 - Technology
33
304 - Factors affecting social behavior
22
610 - Medicine & health
22
370 - Education
7
336 - Public finance
3
340 - Law
1