Classification
140 - Specific philosophical schools
1
320 - Political science
330 - Economics
333 - Economics of land & energy
1
363 - Other social problems & services
380 - Commerce, communications & transportation
581 - Specific topics in natural history
1
600 - Technology
1
620 - Engineering & allied operations
1
700 - The arts; fine & decorative arts
1
900 - History & geography
1