Classification
320 - Political science
330 - Economics
581 - Specific topics in natural history
700 - The arts; fine & decorative arts
900 - History & geography
000 - Computer science, information & general works
4
333 - Economics of land & energy
4
363 - Other social problems & services
4
140 - Specific philosophical schools
3
380 - Commerce, communications & transportation
3
370 - Education
2
551 - Geology, hydrology & meteorology
2
600 - Technology
2
620 - Engineering & allied operations
2
170 - Ethics
1
300 - Social sciences
1
414 - Phonology & phonetics
1
530 - Physics
1
610 - Medicine & health
1