Classification
576 - Genetics & evolution
320 - Political science
4
900 - History & geography
3
140 - Specific philosophical schools
2
330 - Economics
2
304 - Factors affecting social behavior
1
540 - Chemistry & allied sciences
1
580 - Plants (Botany)
1
581 - Specific topics in natural history
1
620 - Engineering & allied operations
1
630 - Agriculture & related technologies
1