Classification
304 - Factors affecting social behavior
380 - Commerce, communications & transportation
3
576 - Genetics & evolution
600 - Technology
700 - The arts; fine & decorative arts
900 - History & geography
2
140 - Specific philosophical schools
1
200 - Religion
1
320 - Political science
1
330 - Economics
1
333 - Economics of land & energy
1
363 - Other social problems & services
1
610 - Medicine & health
1
620 - Engineering & allied operations
1
630 - Agriculture & related technologies
1