Classification
000 - Computer science, information & general works
363 - Other social problems & services
370 - Education
380 - Commerce, communications & transportation
700 - The arts; fine & decorative arts
900 - History & geography
333 - Economics of land & energy
5
600 - Technology
4
320 - Political science
3
330 - Economics
3
620 - Engineering & allied operations
3
720 - Architecture
3
140 - Specific philosophical schools
2
340 - Law
2
551 - Geology, hydrology & meteorology
2
200 - Religion
1
304 - Factors affecting social behavior
1
400 - Language
1
414 - Phonology & phonetics
1
581 - Specific topics in natural history
1
610 - Medicine & health
1