Classification
170 - Ethics
333 - Economics of land & energy
600 - Technology
610 - Medicine & health
620 - Engineering & allied operations
5
700 - The arts; fine & decorative arts
4
900 - History & geography
4
330 - Economics
3
363 - Other social problems & services
3
580 - Plants (Botany)
3
720 - Architecture
3
000 - Computer science, information & general works
2
140 - Specific philosophical schools
2
300 - Social sciences
2
340 - Law
2
380 - Commerce, communications & transportation
2
576 - Genetics & evolution
2
630 - Agriculture & related technologies
2
800 - Literature & rhetoric
2
320 - Political science
1
370 - Education
1
530 - Physics
1
551 - Geology, hydrology & meteorology
1
581 - Specific topics in natural history
1