Classification
330 - Economics
6
363 - Other social problems & services
333 - Economics of land & energy
5
600 - Technology
4
620 - Engineering & allied operations
4
900 - History & geography
4
000 - Computer science, information & general works
3
320 - Political science
3
551 - Geology, hydrology & meteorology
3
700 - The arts; fine & decorative arts
3
580 - Plants (Botany)
2
630 - Agriculture & related technologies
2
800 - Literature & rhetoric
2
380 - Commerce, communications & transportation
1
576 - Genetics & evolution
1