Classification
000 - Computer science, information & general works
304 - Factors affecting social behavior
363 - Other social problems & services
4
551 - Geology, hydrology & meteorology
4
330 - Economics
3
581 - Specific topics in natural history
3
700 - The arts; fine & decorative arts
3
900 - History & geography
3
140 - Specific philosophical schools
2
333 - Economics of land & energy
2
380 - Commerce, communications & transportation
2
576 - Genetics & evolution
2
610 - Medicine & health
2
630 - Agriculture & related technologies
2
320 - Political science
1
361 - Social problems & social welfare in general
1
364 - Criminology
1
370 - Education
1
414 - Phonology & phonetics
1
580 - Plants (Botany)
1
800 - Literature & rhetoric
1