Classification
304 - Factors affecting social behavior
55
320 - Political science
46
330 - Economics
77
333 - Economics of land & energy
31
336 - Public finance
31
363 - Other social problems & services
16
370 - Education
42
380 - Commerce, communications & transportation
12
600 - Technology
15
610 - Medicine & health
55
630 - Agriculture & related technologies
4