Classification
551 - Geology, hydrology & meteorology
363 - Other social problems & services
15
330 - Economics
14
333 - Economics of land & energy
14
000 - Computer science, information & general works
11
320 - Political science
10
380 - Commerce, communications & transportation
7
600 - Technology
7
700 - The arts; fine & decorative arts
7
610 - Medicine & health
4
900 - History & geography
4
140 - Specific philosophical schools
3
304 - Factors affecting social behavior
2
340 - Law
2
370 - Education
2
500 - Natural sciences & mathematics
2
530 - Physics
2
576 - Genetics & evolution
2
580 - Plants (Botany)
2
581 - Specific topics in natural history
2
620 - Engineering & allied operations
2
720 - Architecture
2
300 - Social sciences
1
410 - Linguistics
1
414 - Phonology & phonetics
1
550 - Earth sciences
1
630 - Agriculture & related technologies
1
658 - General management
1
800 - Literature & rhetoric
1