Classification
333 - Economics of land & energy
414 - Phonology & phonetics
551 - Geology, hydrology & meteorology
7
900 - History & geography
000 - Computer science, information & general works
4
363 - Other social problems & services
4
700 - The arts; fine & decorative arts
3
304 - Factors affecting social behavior
2
320 - Political science
2
330 - Economics
2
380 - Commerce, communications & transportation
2
600 - Technology
2
140 - Specific philosophical schools
1
340 - Law
1
370 - Education
1
581 - Specific topics in natural history
1
610 - Medicine & health
1
615 - Pharmacology & therapeutics
1
620 - Engineering & allied operations
1