Classification
330 - Economics
33
333 - Economics of land & energy
12
363 - Other social problems & services
11
600 - Technology
10
700 - The arts; fine & decorative arts
9
000 - Computer science, information & general works
7
620 - Engineering & allied operations
7
900 - History & geography
7
320 - Political science
6
551 - Geology, hydrology & meteorology
5
580 - Plants (Botany)
5
581 - Specific topics in natural history
5
380 - Commerce, communications & transportation
3
540 - Chemistry & allied sciences
3
630 - Agriculture & related technologies
3
100 - Philosophy & psychology
2
140 - Specific philosophical schools
2
170 - Ethics
2
340 - Law
2
530 - Physics
2
610 - Medicine & health
2
615 - Pharmacology & therapeutics
2
200 - Religion
1
370 - Education
1
550 - Earth sciences
1
800 - Literature & rhetoric
1