Classification
100 - Philosophy & psychology
320 - Political science
330 - Economics
600 - Technology
300 - Social sciences
21
900 - History & geography
14
363 - Other social problems & services
11
620 - Engineering & allied operations
9
700 - The arts; fine & decorative arts
9
170 - Ethics
7
610 - Medicine & health
7
333 - Economics of land & energy
6
340 - Law
6
370 - Education
6
780 - Music
6
000 - Computer science, information & general works
4
380 - Commerce, communications & transportation
4
400 - Language
4
140 - Specific philosophical schools
3
301 - Sociology & anthropology
3
410 - Linguistics
3
576 - Genetics & evolution
3
200 - Religion
2
530 - Physics
2
581 - Specific topics in natural history
2
630 - Agriculture & related technologies
2
720 - Architecture
2
770 - Photography, photographs & computer art
2
120 - Epistemology, causation & humankind
1
304 - Factors affecting social behavior
1
350 - Public administration & military science
1
361 - Social problems & social welfare in general
1
364 - Criminology
1
551 - Geology, hydrology & meteorology
1
580 - Plants (Botany)
1
658 - General management
1
791 - Public performances
1