Classification
140 - Specific philosophical schools
300 - Social sciences
320 - Political science
363 - Other social problems & services
333 - Economics of land & energy
5
581 - Specific topics in natural history
4
600 - Technology
4
330 - Economics
3
370 - Education
3
551 - Geology, hydrology & meteorology
3
900 - History & geography
2
000 - Computer science, information & general works
1
340 - Law
1
500 - Natural sciences & mathematics
1
610 - Medicine & health
1
620 - Engineering & allied operations
1
658 - General management
1
800 - Literature & rhetoric
1