Classification
333 - Economics of land & energy
3
363 - Other social problems & services
370 - Education
581 - Specific topics in natural history
900 - History & geography
320 - Political science
2
600 - Technology
2
700 - The arts; fine & decorative arts
2
000 - Computer science, information & general works
1
140 - Specific philosophical schools
1
330 - Economics
1
380 - Commerce, communications & transportation
1
414 - Phonology & phonetics
1
551 - Geology, hydrology & meteorology
1
620 - Engineering & allied operations
1