Classification
900 - History & geography
330 - Economics
12
363 - Other social problems & services
12
000 - Computer science, information & general works
7
551 - Geology, hydrology & meteorology
7
581 - Specific topics in natural history
5
140 - Specific philosophical schools
4
320 - Political science
4
333 - Economics of land & energy
4
700 - The arts; fine & decorative arts
4
380 - Commerce, communications & transportation
2
414 - Phonology & phonetics
2
170 - Ethics
1
530 - Physics
1
550 - Earth sciences
1
590 - Animals (Zoology)
1
600 - Technology
1
610 - Medicine & health
1
620 - Engineering & allied operations
1
720 - Architecture
1