Classification
600 - Technology
152
330 - Economics
67
320 - Political science
27
304 - Factors affecting social behavior
20
610 - Medicine & health
20
363 - Other social problems & services
16
333 - Economics of land & energy
11
370 - Education
9
380 - Commerce, communications & transportation
7
630 - Agriculture & related technologies
5
336 - Public finance
4