Classification
304 - Factors affecting social behavior
123
320 - Political science
252
330 - Economics
559
333 - Economics of land & energy
117
336 - Public finance
20
363 - Other social problems & services
96
370 - Education
106
380 - Commerce, communications & transportation
58
600 - Technology
610 - Medicine & health
123
630 - Agriculture & related technologies
39