Classification
333 - Economics of land & energy
4
700 - The arts; fine & decorative arts
4
330 - Economics
3
600 - Technology
3
000 - Computer science, information & general works
2
363 - Other social problems & services
2
380 - Commerce, communications & transportation
2
620 - Engineering & allied operations
2
900 - History & geography
2
500 - Natural sciences & mathematics
1
551 - Geology, hydrology & meteorology
1
580 - Plants (Botany)
1