Classification
330 - Economics
333 - Economics of land & energy
320 - Political science
345
363 - Other social problems & services
139
304 - Factors affecting social behavior
82
610 - Medicine & health
82
380 - Commerce, communications & transportation
53
600 - Technology
50
370 - Education
36
336 - Public finance
31
630 - Agriculture & related technologies
22
340 - Law
3