Classification
304 - Factors affecting social behavior
320 - Political science
330 - Economics
600 - Technology
900 - History & geography
380 - Commerce, communications & transportation
3
200 - Religion
2
300 - Social sciences
2
370 - Education
2
700 - The arts; fine & decorative arts
2
100 - Philosophy & psychology
1
140 - Specific philosophical schools
1
170 - Ethics
1
301 - Sociology & anthropology
1
333 - Economics of land & energy
1
340 - Law
1
363 - Other social problems & services
1
576 - Genetics & evolution
1
620 - Engineering & allied operations
1
630 - Agriculture & related technologies
1