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