Classification
300 - Social sciences
630 - Agriculture & related technologies
320 - Political science
17
330 - Economics
14
900 - History & geography
8
301 - Sociology & anthropology
5
333 - Economics of land & energy
5
140 - Specific philosophical schools
3
363 - Other social problems & services
3
000 - Computer science, information & general works
2
581 - Specific topics in natural history
2
600 - Technology
2
610 - Medicine & health
2
620 - Engineering & allied operations
2
304 - Factors affecting social behavior
1
361 - Social problems & social welfare in general
1
370 - Education
1
380 - Commerce, communications & transportation
1
580 - Plants (Botany)
1
700 - The arts; fine & decorative arts
1