Classification
520 - Astronomy & allied sciences
44
500 - Natural sciences & mathematics
11
150 - Psychology
10
523 - Specific celestial bodies & phenomena
6
900 - History & geography
3
501 - Philosophy & theory
2
510 - Mathematics
2
530 - Physics
2
142 - Critical philosophy
1
304 - Factors affecting social behavior
1
600 - Technology
1
620 - Engineering & allied operations
1