Classification
320 - Political science
48
330 - Economics
28
340 - Law
21
333 - Economics of land & energy
16
363 - Other social problems & services
12
900 - History & geography
10
370 - Education
9
581 - Specific topics in natural history
9
300 - Social sciences
8
700 - The arts; fine & decorative arts
8
342 - Constitutional & administrative law
7
350 - Public administration & military science
7
600 - Technology
6
321 - Systems of governments & states
5
361 - Social problems & social welfare in general
5
500 - Natural sciences & mathematics
5
100 - Philosophy & psychology
4
140 - Specific philosophical schools
4
338 - Production
4
364 - Criminology
4
620 - Engineering & allied operations
4
323 - Civil & political rights
3
360 - Social problems & services; associations
3
630 - Agriculture & related technologies
3
304 - Factors affecting social behavior
2
336 - Public finance
2
337 - International economics
2
380 - Commerce, communications & transportation
2
551 - Geology, hydrology & meteorology
2
610 - Medicine & health
2
000 - Computer science, information & general works
1
307 - Communities
1
327 - International relations
1
341 - Law of nations
1
347 - Civil procedure & courts
1
351 - Public administration
1
353 - Specific fields of public administration
1
358 - Air & other specialized forces
1
362 - Social welfare problems & services
1
368 - Insurance
1
410 - Linguistics
1
580 - Plants (Botany)
1
607 - Education, research & related topics
1
660 - Chemical engineering
1
945 - Italian Peninsula & adjacent islands
1
947 - Eastern Europe; Russia
1