Classification
304 - Factors affecting social behavior
54
320 - Political science
46
330 - Economics
75
333 - Economics of land & energy
31
336 - Public finance
30
363 - Other social problems & services
16
370 - Education
42
380 - Commerce, communications & transportation
12
600 - Technology
14
610 - Medicine & health
54
630 - Agriculture & related technologies
4