Classification
330 - Economics
3
600 - Technology
610 - Medicine & health
620 - Engineering & allied operations
3
630 - Agriculture & related technologies
333 - Economics of land & energy
2
363 - Other social problems & services
2
140 - Specific philosophical schools
1
540 - Chemistry & allied sciences
1
550 - Earth sciences
1
551 - Geology, hydrology & meteorology
1
580 - Plants (Botany)
1
581 - Specific topics in natural history
1
900 - History & geography
1