Classification
330 - Economics
9
540 - Chemistry & allied sciences
600 - Technology
620 - Engineering & allied operations
8
333 - Economics of land & energy
5
363 - Other social problems & services
4
700 - The arts; fine & decorative arts
3
900 - History & geography
3
320 - Political science
2
580 - Plants (Botany)
2
380 - Commerce, communications & transportation
1
414 - Phonology & phonetics
1
551 - Geology, hydrology & meteorology
1
581 - Specific topics in natural history
1
658 - General management
1
720 - Architecture
1
800 - Literature & rhetoric
1