Classification
333 - Economics of land & energy
551 - Geology, hydrology & meteorology
600 - Technology
620 - Engineering & allied operations
31
363 - Other social problems & services
27
330 - Economics
24
900 - History & geography
21
000 - Computer science, information & general works
20
700 - The arts; fine & decorative arts
20
610 - Medicine & health
14
580 - Plants (Botany)
12
380 - Commerce, communications & transportation
11
630 - Agriculture & related technologies
11
320 - Political science
10
720 - Architecture
9
370 - Education
7
140 - Specific philosophical schools
4
500 - Natural sciences & mathematics
4
658 - General management
4
800 - Literature & rhetoric
4
340 - Law
3
530 - Physics
3
540 - Chemistry & allied sciences
3
581 - Specific topics in natural history
2
100 - Philosophy & psychology
1
170 - Ethics
1
304 - Factors affecting social behavior
1
336 - Public finance
1
360 - Social problems & services; associations
1
361 - Social problems & social welfare in general
1
410 - Linguistics
1
576 - Genetics & evolution
1