Classification
577 - Ecology
47
333 - Economics of land & energy
16
551 - Geology, hydrology & meteorology
16
338 - Production
14
630 - Agriculture & related technologies
6
363 - Other social problems & services
5
304 - Factors affecting social behavior
3
550 - Earth sciences
3
571 - Physiology & related subjects
3
500 - Natural sciences & mathematics
2
624 - Civil engineering
2
919 - Geography of & travel in other areas
2
930 - History of ancient world to ca. 499
2
300 - Social sciences
1
301 - Sociology & anthropology
1
320 - Political science
1
327 - International relations
1
364 - Criminology
1
519 - Probabilities & applied mathematics
1
526 - Mathematical geography
1
560 - Paleontology; paleozoology
1
579 - Microorganisms, fungi & algae
1
581 - Specific topics in natural history
1
595 - Arthropods
1
613 - Personal health & safety
1
614 - Incidence & prevention of disease
1
621 - Applied physics
1
628 - Sanitary & municipal engineering
1
634 - Orchards, fruits & forestry
1
658 - General management
1
660 - Chemical engineering
1
690 - Buildings
1
700 - The arts; fine & decorative arts
1
720 - Architecture
1
900 - History & geography
1
910 - Geography & travel
1