Classification
333 - Economics of land & energy
5
551 - Geology, hydrology & meteorology
4
577 - Ecology
4
621 - Applied physics
3
304 - Factors affecting social behavior
2
630 - Agriculture & related technologies
2
910 - Geography & travel
2
036 - Encyclopedias in Spanish & Portuguese
1
330 - Economics
1
331 - Labor economics
1
363 - Other social problems & services
1
550 - Earth sciences
1
570 - Life sciences; biology
1
600 - Technology
1
610 - Medicine & health
1
631 - Techniques, equipment & materials
1