Classification
500 - Natural sciences & mathematics
520 - Astronomy & allied sciences
17
620 - Engineering & allied operations
8
363 - Other social problems & services
5
700 - The arts; fine & decorative arts
4
900 - History & geography
4
000 - Computer science, information & general works
3
551 - Geology, hydrology & meteorology
3
577 - Ecology
2
600 - Technology
2
610 - Medicine & health
2
720 - Architecture
2
100 - Philosophy & psychology
1
140 - Specific philosophical schools
1
153 - Mental processes & intelligence
1
158 - Applied psychology
1
200 - Religion
1
507 - Education, research & related topics
1
509 - Historical, geographic & persons treatment
1
530 - Physics
1
549 - Mineralogy
1
576 - Genetics & evolution
1
580 - Plants (Botany)
1
581 - Specific topics in natural history
1
621 - Applied physics
1
622 - Mining & related operations
1
658 - General management
1