Classification
200 - Religion
600 - Technology
320 - Political science
3
630 - Agriculture & related technologies
3
100 - Philosophy & psychology
2
140 - Specific philosophical schools
2
304 - Factors affecting social behavior
2
330 - Economics
2
551 - Geology, hydrology & meteorology
2
581 - Specific topics in natural history
2
620 - Engineering & allied operations
2
900 - History & geography
2
300 - Social sciences
1
333 - Economics of land & energy
1
380 - Commerce, communications & transportation
1
576 - Genetics & evolution
1
610 - Medicine & health
1
700 - The arts; fine & decorative arts
1
791 - Public performances
1