Classification
330 - Economics
600 - Technology
3
620 - Engineering & allied operations
700 - The arts; fine & decorative arts
3
900 - History & geography
3
333 - Economics of land & energy
2
370 - Education
2
140 - Specific philosophical schools
1
363 - Other social problems & services
1
380 - Commerce, communications & transportation
1
551 - Geology, hydrology & meteorology
1