Classification
320 - Political science
330 - Economics
363 - Other social problems & services
900 - History & geography
140 - Specific philosophical schools
2
333 - Economics of land & energy
2
551 - Geology, hydrology & meteorology
2
581 - Specific topics in natural history
2
600 - Technology
2
620 - Engineering & allied operations
2
700 - The arts; fine & decorative arts
2
380 - Commerce, communications & transportation
1
580 - Plants (Botany)
1