Classification
577 - Ecology
13
000 - Computer science, information & general works
10
570 - Life sciences; biology
9
610 - Medicine & health
8
700 - The arts; fine & decorative arts
8
576 - Genetics & evolution
7
581 - Specific topics in natural history
7
500 - Natural sciences & mathematics
6
304 - Factors affecting social behavior
5
515 - Analysis
5
333 - Economics of land & energy
4
363 - Other social problems & services
4
519 - Probabilities & applied mathematics
4
300 - Social sciences
3
320 - Political science
3
510 - Mathematics
3
580 - Plants (Botany)
3
305 - Social groups
2
330 - Economics
2
338 - Production
2
551 - Geology, hydrology & meteorology
2
600 - Technology
2
614 - Incidence & prevention of disease
2
630 - Agriculture & related technologies
2
900 - History & geography
2
140 - Specific philosophical schools
1
340 - Law
1
370 - Education
1
530 - Physics
1
540 - Chemistry & allied sciences
1
560 - Paleontology; paleozoology
1
571 - Physiology & related subjects
1
578 - Natural history of organisms
1
591 - Specific topics in natural history
1
612 - Human physiology
1
613 - Personal health & safety
1
620 - Engineering & allied operations
1
621 - Applied physics
1
657 - Accounting
1
658 - General management
1