Classification
333 - Economics of land & energy
3
363 - Other social problems & services
380 - Commerce, communications & transportation
658 - General management
800 - Literature & rhetoric
330 - Economics
2
600 - Technology
2
620 - Engineering & allied operations
2
700 - The arts; fine & decorative arts
2
140 - Specific philosophical schools
1
320 - Political science
1
336 - Public finance
1
361 - Social problems & social welfare in general
1
370 - Education
1
551 - Geology, hydrology & meteorology
1
576 - Genetics & evolution
1
580 - Plants (Botany)
1
610 - Medicine & health
1
900 - History & geography
1